--- a/Cargo.lock
+++ b/Cargo.lock
@@ -5,16 +5,22 @@
 version = "0.1.0"
 dependencies = [
  "jsonnet-parser",
+ "jsonnet-stdlib",
 ]
 
 [[package]]
 name = "jsonnet-parser"
 version = "0.1.0"
 dependencies = [
+ "jsonnet-stdlib",
  "peg",
 ]
 
 [[package]]
+name = "jsonnet-stdlib"
+version = "0.1.0"
+
+[[package]]
 name = "peg"
 version = "0.6.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -2,4 +2,5 @@
 members = [
 	"crates/jsonnet-parser",
 	"crates/jsonnet-evaluator",
+	"crates/jsonnet-stdlib",
 ]
--- /dev/null
+++ b/crates/jsonnet-stdlib/Cargo.toml
@@ -0,0 +1,9 @@
+[package]
+name = "jsonnet-stdlib"
+version = "0.1.0"
+authors = ["Лач <iam@lach.pw>"]
+edition = "2018"
+
+[features]
+
+[dependencies]
--- /dev/null
+++ b/crates/jsonnet-stdlib/README.md
@@ -0,0 +1,3 @@
+# jsonnet-stdlib
+
+Jsonnet standard library packaged as crate
--- /dev/null
+++ b/crates/jsonnet-stdlib/src/lib.rs
@@ -0,0 +1 @@
+pub const STDLIB_STR: &'static str = include_str!("./std.jsonnet");
--- /dev/null
+++ b/crates/jsonnet-stdlib/src/std.jsonnet
@@ -0,0 +1,1345 @@
+{
+
+  local std = self,
+  local id = function(x) x,
+
+  isString(v):: std.type(v) == 'string',
+  isNumber(v):: std.type(v) == 'number',
+  isBoolean(v):: std.type(v) == 'boolean',
+  isObject(v):: std.type(v) == 'object',
+  isArray(v):: std.type(v) == 'array',
+  isFunction(v):: std.type(v) == 'function',
+
+  toString(a)::
+    if std.type(a) == 'string' then a else '' + a,
+
+  substr(str, from, len)::
+    assert std.isString(str) : 'substr first parameter should be a string, got ' + std.type(str);
+    assert std.isNumber(from) : 'substr second parameter should be a string, got ' + std.type(from);
+    assert std.isNumber(len) : 'substr third parameter should be a string, got ' + std.type(len);
+    assert len >= 0 : 'substr third parameter should be greater than zero, got ' + len;
+    std.join('', std.makeArray(std.max(0, std.min(len, std.length(str) - from)), function(i) str[i + from])),
+
+  startsWith(a, b)::
+    if std.length(a) < std.length(b) then
+      false
+    else
+      std.substr(a, 0, std.length(b)) == b,
+
+  endsWith(a, b)::
+    if std.length(a) < std.length(b) then
+      false
+    else
+      std.substr(a, std.length(a) - std.length(b), std.length(b)) == b,
+
+  lstripChars(str, chars)::
+    if std.length(str) > 0 && std.member(chars, str[0]) then
+      std.lstripChars(str[1:], chars)
+    else
+      str,
+
+  rstripChars(str, chars)::
+    local len = std.length(str);
+    if len > 0 && std.member(chars, str[len - 1]) then
+      std.rstripChars(str[:len - 1], chars)
+    else
+      str,
+
+  stripChars(str, chars)::
+    std.lstripChars(std.rstripChars(str, chars), chars),
+
+  stringChars(str)::
+    std.makeArray(std.length(str), function(i) str[i]),
+
+  local parse_nat(str, base) =
+    assert base > 0 && base <= 16 : 'integer base %d invalid' % base;
+    // These codepoints are in ascending order:
+    local zero_code = std.codepoint('0');
+    local upper_a_code = std.codepoint('A');
+    local lower_a_code = std.codepoint('a');
+    local addDigit(aggregate, char) =
+      local code = std.codepoint(char);
+      local digit = if code >= lower_a_code then
+        code - lower_a_code + 10
+      else if code >= upper_a_code then
+        code - upper_a_code + 10
+      else
+        code - zero_code;
+      assert digit >= 0 && digit < base : '%s is not a base %d integer' % [str, base];
+      base * aggregate + digit;
+    std.foldl(addDigit, std.stringChars(str), 0),
+
+  parseInt(str)::
+    assert std.isString(str) : 'Expected string, got ' + std.type(str);
+    assert std.length(str) > 0 && str != '-' : 'Not an integer: "%s"' % [str];
+    if str[0] == '-' then
+      -parse_nat(str[1:], 10)
+    else
+      parse_nat(str, 10),
+
+  parseOctal(str)::
+    assert std.isString(str) : 'Expected string, got ' + std.type(str);
+    assert std.length(str) > 0 : 'Not an octal number: ""';
+    parse_nat(str, 8),
+
+  parseHex(str)::
+    assert std.isString(str) : 'Expected string, got ' + std.type(str);
+    assert std.length(str) > 0 : 'Not hexadecimal: ""';
+    parse_nat(str, 16),
+
+  split(str, c)::
+    assert std.isString(str) : 'std.split first parameter should be a string, got ' + std.type(str);
+    assert std.isString(c) : 'std.split second parameter should be a string, got ' + std.type(c);
+    assert std.length(c) == 1 : 'std.split second parameter should have length 1, got ' + std.length(c);
+    std.splitLimit(str, c, -1),
+
+  splitLimit(str, c, maxsplits)::
+    assert std.isString(str) : 'std.splitLimit first parameter should be a string, got ' + std.type(str);
+    assert std.isString(c) : 'std.splitLimit second parameter should be a string, got ' + std.type(c);
+    assert std.length(c) == 1 : 'std.splitLimit second parameter should have length 1, got ' + std.length(c);
+    assert std.isNumber(maxsplits) : 'std.splitLimit third parameter should be a number, got ' + std.type(maxsplits);
+    local aux(str, delim, i, arr, v) =
+      local c = str[i];
+      local i2 = i + 1;
+      if i >= std.length(str) then
+        arr + [v]
+      else if c == delim && (maxsplits == -1 || std.length(arr) < maxsplits) then
+        aux(str, delim, i2, arr + [v], '') tailstrict
+      else
+        aux(str, delim, i2, arr, v + c) tailstrict;
+    aux(str, c, 0, [], ''),
+
+  strReplace(str, from, to)::
+    assert std.isString(str);
+    assert std.isString(from);
+    assert std.isString(to);
+    assert from != '' : "'from' string must not be zero length.";
+
+    // Cache for performance.
+    local str_len = std.length(str);
+    local from_len = std.length(from);
+
+    // True if from is at str[i].
+    local found_at(i) = str[i:i + from_len] == from;
+
+    // Return the remainder of 'str' starting with 'start_index' where
+    // all occurrences of 'from' after 'curr_index' are replaced with 'to'.
+    local replace_after(start_index, curr_index, acc) =
+      if curr_index > str_len then
+        acc + str[start_index:curr_index]
+      else if found_at(curr_index) then
+        local new_index = curr_index + std.length(from);
+        replace_after(new_index, new_index, acc + str[start_index:curr_index] + to) tailstrict
+      else
+        replace_after(start_index, curr_index + 1, acc) tailstrict;
+
+    // if from_len==1, then we replace by splitting and rejoining the
+    // string which is much faster than recursing on replace_after
+    if from_len == 1 then
+      std.join(to, std.split(str, from))
+    else
+      replace_after(0, 0, ''),
+
+  asciiUpper(str)::
+    local cp = std.codepoint;
+    local up_letter(c) = if cp(c) >= 97 && cp(c) < 123 then
+      std.char(cp(c) - 32)
+    else
+      c;
+    std.join('', std.map(up_letter, std.stringChars(str))),
+
+  asciiLower(str)::
+    local cp = std.codepoint;
+    local down_letter(c) = if cp(c) >= 65 && cp(c) < 91 then
+      std.char(cp(c) + 32)
+    else
+      c;
+    std.join('', std.map(down_letter, std.stringChars(str))),
+
+  range(from, to)::
+    std.makeArray(to - from + 1, function(i) i + from),
+
+  repeat(what, count)::
+    local joiner =
+      if std.isString(what) then ''
+      else if std.isArray(what) then []
+      else error 'std.repeat first argument must be an array or a string';
+    std.join(joiner, std.makeArray(count, function(i) what)),
+
+  slice(indexable, index, end, step)::
+    local invar =
+      // loop invariant with defaults applied
+      {
+        indexable: indexable,
+        index:
+          if index == null then 0
+          else index,
+        end:
+          if end == null then std.length(indexable)
+          else end,
+        step:
+          if step == null then 1
+          else step,
+        length: std.length(indexable),
+        type: std.type(indexable),
+      };
+    assert invar.index >= 0 && invar.end >= 0 && invar.step >= 0 : 'got [%s:%s:%s] but negative index, end, and steps are not supported' % [invar.index, invar.end, invar.step];
+    assert step != 0 : 'got %s but step must be greater than 0' % step;
+    assert std.isString(indexable) || std.isArray(indexable) : 'std.slice accepts a string or an array, but got: %s' % std.type(indexable);
+    local build(slice, cur) =
+      if cur >= invar.end || cur >= invar.length then
+        slice
+      else
+        build(
+          if invar.type == 'string' then
+            slice + invar.indexable[cur]
+          else
+            slice + [invar.indexable[cur]],
+          cur + invar.step
+        ) tailstrict;
+    build(if invar.type == 'string' then '' else [], invar.index),
+
+  member(arr, x)::
+    if std.isArray(arr) then
+      std.count(arr, x) > 0
+    else if std.isString(arr) then
+      std.length(std.findSubstr(x, arr)) > 0
+    else error 'std.member first argument must be an array or a string',
+
+  count(arr, x):: std.length(std.filter(function(v) v == x, arr)),
+
+  mod(a, b)::
+    if std.isNumber(a) && std.isNumber(b) then
+      std.modulo(a, b)
+    else if std.isString(a) then
+      std.format(a, b)
+    else
+      error 'Operator % cannot be used on types ' + std.type(a) + ' and ' + std.type(b) + '.',
+
+  map(func, arr)::
+    if !std.isFunction(func) then
+      error ('std.map first param must be function, got ' + std.type(func))
+    else if !std.isArray(arr) && !std.isString(arr) then
+      error ('std.map second param must be array / string, got ' + std.type(arr))
+    else
+      std.makeArray(std.length(arr), function(i) func(arr[i])),
+
+  mapWithIndex(func, arr)::
+    if !std.isFunction(func) then
+      error ('std.mapWithIndex first param must be function, got ' + std.type(func))
+    else if !std.isArray(arr) && !std.isString(arr) then
+      error ('std.mapWithIndex second param must be array, got ' + std.type(arr))
+    else
+      std.makeArray(std.length(arr), function(i) func(i, arr[i])),
+
+  mapWithKey(func, obj)::
+    if !std.isFunction(func) then
+      error ('std.mapWithKey first param must be function, got ' + std.type(func))
+    else if !std.isObject(obj) then
+      error ('std.mapWithKey second param must be object, got ' + std.type(obj))
+    else
+      { [k]: func(k, obj[k]) for k in std.objectFields(obj) },
+
+  flatMap(func, arr)::
+    if !std.isFunction(func) then
+      error ('std.flatMap first param must be function, got ' + std.type(func))
+    else if std.isArray(arr) then
+      std.flattenArrays(std.makeArray(std.length(arr), function(i) func(arr[i])))
+    else if std.isString(arr) then
+      std.join('', std.makeArray(std.length(arr), function(i) func(arr[i])))
+    else error ('std.flatMap second param must be array / string, got ' + std.type(arr)),
+
+  join(sep, arr)::
+    local aux(arr, i, first, running) =
+      if i >= std.length(arr) then
+        running
+      else if arr[i] == null then
+        aux(arr, i + 1, first, running) tailstrict
+      else if std.type(arr[i]) != std.type(sep) then
+        error 'expected %s but arr[%d] was %s ' % [std.type(sep), i, std.type(arr[i])]
+      else if first then
+        aux(arr, i + 1, false, running + arr[i]) tailstrict
+      else
+        aux(arr, i + 1, false, running + sep + arr[i]) tailstrict;
+    if !std.isArray(arr) then
+      error 'join second parameter should be array, got ' + std.type(arr)
+    else if std.isString(sep) then
+      aux(arr, 0, true, '')
+    else if std.isArray(sep) then
+      aux(arr, 0, true, [])
+    else
+      error 'join first parameter should be string or array, got ' + std.type(sep),
+
+  lines(arr)::
+    std.join('\n', arr + ['']),
+
+  deepJoin(arr)::
+    if std.isString(arr) then
+      arr
+    else if std.isArray(arr) then
+      std.join('', [std.deepJoin(x) for x in arr])
+    else
+      error 'Expected string or array, got %s' % std.type(arr),
+
+
+  format(str, vals)::
+
+    /////////////////////////////
+    // Parse the mini-language //
+    /////////////////////////////
+
+    local try_parse_mapping_key(str, i) =
+      assert i < std.length(str) : 'Truncated format code.';
+      local c = str[i];
+      if c == '(' then
+        local consume(str, j, v) =
+          if j >= std.length(str) then
+            error 'Truncated format code.'
+          else
+            local c = str[j];
+            if c != ')' then
+              consume(str, j + 1, v + c)
+            else
+              { i: j + 1, v: v };
+        consume(str, i + 1, '')
+      else
+        { i: i, v: null };
+
+    local try_parse_cflags(str, i) =
+      local consume(str, j, v) =
+        assert j < std.length(str) : 'Truncated format code.';
+        local c = str[j];
+        if c == '#' then
+          consume(str, j + 1, v { alt: true })
+        else if c == '0' then
+          consume(str, j + 1, v { zero: true })
+        else if c == '-' then
+          consume(str, j + 1, v { left: true })
+        else if c == ' ' then
+          consume(str, j + 1, v { blank: true })
+        else if c == '+' then
+          consume(str, j + 1, v { sign: true })
+        else
+          { i: j, v: v };
+      consume(str, i, { alt: false, zero: false, left: false, blank: false, sign: false });
+
+    local try_parse_field_width(str, i) =
+      if i < std.length(str) && str[i] == '*' then
+        { i: i + 1, v: '*' }
+      else
+        local consume(str, j, v) =
+          assert j < std.length(str) : 'Truncated format code.';
+          local c = str[j];
+          if c == '0' then
+            consume(str, j + 1, v * 10 + 0)
+          else if c == '1' then
+            consume(str, j + 1, v * 10 + 1)
+          else if c == '2' then
+            consume(str, j + 1, v * 10 + 2)
+          else if c == '3' then
+            consume(str, j + 1, v * 10 + 3)
+          else if c == '4' then
+            consume(str, j + 1, v * 10 + 4)
+          else if c == '5' then
+            consume(str, j + 1, v * 10 + 5)
+          else if c == '6' then
+            consume(str, j + 1, v * 10 + 6)
+          else if c == '7' then
+            consume(str, j + 1, v * 10 + 7)
+          else if c == '8' then
+            consume(str, j + 1, v * 10 + 8)
+          else if c == '9' then
+            consume(str, j + 1, v * 10 + 9)
+          else
+            { i: j, v: v };
+        consume(str, i, 0);
+
+    local try_parse_precision(str, i) =
+      assert i < std.length(str) : 'Truncated format code.';
+      local c = str[i];
+      if c == '.' then
+        try_parse_field_width(str, i + 1)
+      else
+        { i: i, v: null };
+
+    // Ignored, if it exists.
+    local try_parse_length_modifier(str, i) =
+      assert i < std.length(str) : 'Truncated format code.';
+      local c = str[i];
+      if c == 'h' || c == 'l' || c == 'L' then
+        i + 1
+      else
+        i;
+
+    local parse_conv_type(str, i) =
+      assert i < std.length(str) : 'Truncated format code.';
+      local c = str[i];
+      if c == 'd' || c == 'i' || c == 'u' then
+        { i: i + 1, v: 'd', caps: false }
+      else if c == 'o' then
+        { i: i + 1, v: 'o', caps: false }
+      else if c == 'x' then
+        { i: i + 1, v: 'x', caps: false }
+      else if c == 'X' then
+        { i: i + 1, v: 'x', caps: true }
+      else if c == 'e' then
+        { i: i + 1, v: 'e', caps: false }
+      else if c == 'E' then
+        { i: i + 1, v: 'e', caps: true }
+      else if c == 'f' then
+        { i: i + 1, v: 'f', caps: false }
+      else if c == 'F' then
+        { i: i + 1, v: 'f', caps: true }
+      else if c == 'g' then
+        { i: i + 1, v: 'g', caps: false }
+      else if c == 'G' then
+        { i: i + 1, v: 'g', caps: true }
+      else if c == 'c' then
+        { i: i + 1, v: 'c', caps: false }
+      else if c == 's' then
+        { i: i + 1, v: 's', caps: false }
+      else if c == '%' then
+        { i: i + 1, v: '%', caps: false }
+      else
+        error 'Unrecognised conversion type: ' + c;
+
+
+    // Parsed initial %, now the rest.
+    local parse_code(str, i) =
+      assert i < std.length(str) : 'Truncated format code.';
+      local mkey = try_parse_mapping_key(str, i);
+      local cflags = try_parse_cflags(str, mkey.i);
+      local fw = try_parse_field_width(str, cflags.i);
+      local prec = try_parse_precision(str, fw.i);
+      local len_mod = try_parse_length_modifier(str, prec.i);
+      local ctype = parse_conv_type(str, len_mod);
+      {
+        i: ctype.i,
+        code: {
+          mkey: mkey.v,
+          cflags: cflags.v,
+          fw: fw.v,
+          prec: prec.v,
+          ctype: ctype.v,
+          caps: ctype.caps,
+        },
+      };
+
+    // Parse a format string (containing none or more % format tags).
+    local parse_codes(str, i, out, cur) =
+      if i >= std.length(str) then
+        out + [cur]
+      else
+        local c = str[i];
+        if c == '%' then
+          local r = parse_code(str, i + 1);
+          parse_codes(str, r.i, out + [cur, r.code], '') tailstrict
+        else
+          parse_codes(str, i + 1, out, cur + c) tailstrict;
+
+    local codes = parse_codes(str, 0, [], '');
+
+
+    ///////////////////////
+    // Format the values //
+    ///////////////////////
+
+    // Useful utilities
+    local padding(w, s) =
+      local aux(w, v) =
+        if w <= 0 then
+          v
+        else
+          aux(w - 1, v + s);
+      aux(w, '');
+
+    // Add s to the left of str so that its length is at least w.
+    local pad_left(str, w, s) =
+      padding(w - std.length(str), s) + str;
+
+    // Add s to the right of str so that its length is at least w.
+    local pad_right(str, w, s) =
+      str + padding(w - std.length(str), s);
+
+    // Render an integer (e.g., decimal or octal).
+    local render_int(n__, min_chars, min_digits, blank, sign, radix, zero_prefix) =
+      local n_ = std.abs(n__);
+      local aux(n) =
+        if n == 0 then
+          zero_prefix
+        else
+          aux(std.floor(n / radix)) + (n % radix);
+      local dec = if std.floor(n_) == 0 then '0' else aux(std.floor(n_));
+      local neg = n__ < 0;
+      local zp = min_chars - (if neg || blank || sign then 1 else 0);
+      local zp2 = std.max(zp, min_digits);
+      local dec2 = pad_left(dec, zp2, '0');
+      (if neg then '-' else if sign then '+' else if blank then ' ' else '') + dec2;
+
+    // Render an integer in hexadecimal.
+    local render_hex(n__, min_chars, min_digits, blank, sign, add_zerox, capitals) =
+      local numerals = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
+                       + if capitals then ['A', 'B', 'C', 'D', 'E', 'F']
+                       else ['a', 'b', 'c', 'd', 'e', 'f'];
+      local n_ = std.abs(n__);
+      local aux(n) =
+        if n == 0 then
+          ''
+        else
+          aux(std.floor(n / 16)) + numerals[n % 16];
+      local hex = if std.floor(n_) == 0 then '0' else aux(std.floor(n_));
+      local neg = n__ < 0;
+      local zp = min_chars - (if neg || blank || sign then 1 else 0)
+                 - (if add_zerox then 2 else 0);
+      local zp2 = std.max(zp, min_digits);
+      local hex2 = (if add_zerox then (if capitals then '0X' else '0x') else '')
+                   + pad_left(hex, zp2, '0');
+      (if neg then '-' else if sign then '+' else if blank then ' ' else '') + hex2;
+
+    local strip_trailing_zero(str) =
+      local aux(str, i) =
+        if i < 0 then
+          ''
+        else
+          if str[i] == '0' then
+            aux(str, i - 1)
+          else
+            std.substr(str, 0, i + 1);
+      aux(str, std.length(str) - 1);
+
+    // Render floating point in decimal form
+    local render_float_dec(n__, zero_pad, blank, sign, ensure_pt, trailing, prec) =
+      local n_ = std.abs(n__);
+      local whole = std.floor(n_);
+      local dot_size = if prec == 0 && !ensure_pt then 0 else 1;
+      local zp = zero_pad - prec - dot_size;
+      local str = render_int(std.sign(n__) * whole, zp, 0, blank, sign, 10, '');
+      if prec == 0 then
+        str + if ensure_pt then '.' else ''
+      else
+        local frac = std.floor((n_ - whole) * std.pow(10, prec) + 0.5);
+        if trailing || frac > 0 then
+          local frac_str = render_int(frac, prec, 0, false, false, 10, '');
+          str + '.' + if !trailing then strip_trailing_zero(frac_str) else frac_str
+        else
+          str;
+
+    // Render floating point in scientific form
+    local render_float_sci(n__, zero_pad, blank, sign, ensure_pt, trailing, caps, prec) =
+      local exponent = if n__ == 0 then 0 else std.floor(std.log(std.abs(n__)) / std.log(10));
+      local suff = (if caps then 'E' else 'e')
+                   + render_int(exponent, 3, 0, false, true, 10, '');
+      local mantissa = if exponent == -324 then
+        // Avoid a rounding error where std.pow(10, -324) is 0
+        // -324 is the smallest exponent possible.
+        n__ * 10 / std.pow(10, exponent + 1)
+      else
+        n__ / std.pow(10, exponent);
+      local zp2 = zero_pad - std.length(suff);
+      render_float_dec(mantissa, zp2, blank, sign, ensure_pt, trailing, prec) + suff;
+
+    // Render a value with an arbitrary format code.
+    local format_code(val, code, fw, prec_or_null, i) =
+      local cflags = code.cflags;
+      local fpprec = if prec_or_null != null then prec_or_null else 6;
+      local iprec = if prec_or_null != null then prec_or_null else 0;
+      local zp = if cflags.zero && !cflags.left then fw else 0;
+      if code.ctype == 's' then
+        std.toString(val)
+      else if code.ctype == 'd' then
+        if std.type(val) != 'number' then
+          error 'Format required number at '
+                + i + ', got ' + std.type(val)
+        else
+          render_int(val, zp, iprec, cflags.blank, cflags.sign, 10, '')
+      else if code.ctype == 'o' then
+        if std.type(val) != 'number' then
+          error 'Format required number at '
+                + i + ', got ' + std.type(val)
+        else
+          local zero_prefix = if cflags.alt then '0' else '';
+          render_int(val, zp, iprec, cflags.blank, cflags.sign, 8, zero_prefix)
+      else if code.ctype == 'x' then
+        if std.type(val) != 'number' then
+          error 'Format required number at '
+                + i + ', got ' + std.type(val)
+        else
+          render_hex(val,
+                     zp,
+                     iprec,
+                     cflags.blank,
+                     cflags.sign,
+                     cflags.alt,
+                     code.caps)
+      else if code.ctype == 'f' then
+        if std.type(val) != 'number' then
+          error 'Format required number at '
+                + i + ', got ' + std.type(val)
+        else
+          render_float_dec(val,
+                           zp,
+                           cflags.blank,
+                           cflags.sign,
+                           cflags.alt,
+                           true,
+                           fpprec)
+      else if code.ctype == 'e' then
+        if std.type(val) != 'number' then
+          error 'Format required number at '
+                + i + ', got ' + std.type(val)
+        else
+          render_float_sci(val,
+                           zp,
+                           cflags.blank,
+                           cflags.sign,
+                           cflags.alt,
+                           true,
+                           code.caps,
+                           fpprec)
+      else if code.ctype == 'g' then
+        if std.type(val) != 'number' then
+          error 'Format required number at '
+                + i + ', got ' + std.type(val)
+        else
+          local exponent = std.floor(std.log(std.abs(val)) / std.log(10));
+          if exponent < -4 || exponent >= fpprec then
+            render_float_sci(val,
+                             zp,
+                             cflags.blank,
+                             cflags.sign,
+                             cflags.alt,
+                             cflags.alt,
+                             code.caps,
+                             fpprec - 1)
+          else
+            local digits_before_pt = std.max(1, exponent + 1);
+            render_float_dec(val,
+                             zp,
+                             cflags.blank,
+                             cflags.sign,
+                             cflags.alt,
+                             cflags.alt,
+                             fpprec - digits_before_pt)
+      else if code.ctype == 'c' then
+        if std.type(val) == 'number' then
+          std.char(val)
+        else if std.type(val) == 'string' then
+          if std.length(val) == 1 then
+            val
+          else
+            error '%c expected 1-sized string got: ' + std.length(val)
+        else
+          error '%c expected number / string, got: ' + std.type(val)
+      else
+        error 'Unknown code: ' + code.ctype;
+
+    // Render a parsed format string with an array of values.
+    local format_codes_arr(codes, arr, i, j, v) =
+      if i >= std.length(codes) then
+        if j < std.length(arr) then
+          error ('Too many values to format: ' + std.length(arr) + ', expected ' + j)
+        else
+          v
+      else
+        local code = codes[i];
+        if std.type(code) == 'string' then
+          format_codes_arr(codes, arr, i + 1, j, v + code) tailstrict
+        else
+          local tmp = if code.fw == '*' then {
+            j: j + 1,
+            fw: if j >= std.length(arr) then
+              error ('Not enough values to format: ' + std.length(arr) + ', expected at least ' + j)
+            else
+              arr[j],
+          } else {
+            j: j,
+            fw: code.fw,
+          };
+          local tmp2 = if code.prec == '*' then {
+            j: tmp.j + 1,
+            prec: if tmp.j >= std.length(arr) then
+              error ('Not enough values to format: ' + std.length(arr) + ', expected at least ' + tmp.j)
+            else
+              arr[tmp.j],
+          } else {
+            j: tmp.j,
+            prec: code.prec,
+          };
+          local j2 = tmp2.j;
+          local val =
+            if j2 < std.length(arr) then
+              arr[j2]
+            else
+              error ('Not enough values to format: ' + std.length(arr) + ', expected more than ' + j2);
+          local s =
+            if code.ctype == '%' then
+              '%'
+            else
+              format_code(val, code, tmp.fw, tmp2.prec, j2);
+          local s_padded =
+            if code.cflags.left then
+              pad_right(s, tmp.fw, ' ')
+            else
+              pad_left(s, tmp.fw, ' ');
+          local j3 =
+            if code.ctype == '%' then
+              j2
+            else
+              j2 + 1;
+          format_codes_arr(codes, arr, i + 1, j3, v + s_padded) tailstrict;
+
+    // Render a parsed format string with an object of values.
+    local format_codes_obj(codes, obj, i, v) =
+      if i >= std.length(codes) then
+        v
+      else
+        local code = codes[i];
+        if std.type(code) == 'string' then
+          format_codes_obj(codes, obj, i + 1, v + code) tailstrict
+        else
+          local f =
+            if code.mkey == null then
+              error 'Mapping keys required.'
+            else
+              code.mkey;
+          local fw =
+            if code.fw == '*' then
+              error 'Cannot use * field width with object.'
+            else
+              code.fw;
+          local prec =
+            if code.prec == '*' then
+              error 'Cannot use * precision with object.'
+            else
+              code.prec;
+          local val =
+            if std.objectHasAll(obj, f) then
+              obj[f]
+            else
+              error 'No such field: ' + f;
+          local s =
+            if code.ctype == '%' then
+              '%'
+            else
+              format_code(val, code, fw, prec, f);
+          local s_padded =
+            if code.cflags.left then
+              pad_right(s, fw, ' ')
+            else
+              pad_left(s, fw, ' ');
+          format_codes_obj(codes, obj, i + 1, v + s_padded) tailstrict;
+
+    if std.isArray(vals) then
+      format_codes_arr(codes, vals, 0, 0, '')
+    else if std.isObject(vals) then
+      format_codes_obj(codes, vals, 0, '')
+    else
+      format_codes_arr(codes, [vals], 0, 0, ''),
+
+  foldr(func, arr, init)::
+    local aux(func, arr, running, idx) =
+      if idx < 0 then
+        running
+      else
+        aux(func, arr, func(arr[idx], running), idx - 1) tailstrict;
+    aux(func, arr, init, std.length(arr) - 1),
+
+  foldl(func, arr, init)::
+    local aux(func, arr, running, idx) =
+      if idx >= std.length(arr) then
+        running
+      else
+        aux(func, arr, func(running, arr[idx]), idx + 1) tailstrict;
+    aux(func, arr, init, 0),
+
+
+  filterMap(filter_func, map_func, arr)::
+    if !std.isFunction(filter_func) then
+      error ('std.filterMap first param must be function, got ' + std.type(filter_func))
+    else if !std.isFunction(map_func) then
+      error ('std.filterMap second param must be function, got ' + std.type(map_func))
+    else if !std.isArray(arr) then
+      error ('std.filterMap third param must be array, got ' + std.type(arr))
+    else
+      std.map(map_func, std.filter(filter_func, arr)),
+
+  assertEqual(a, b)::
+    if a == b then
+      true
+    else
+      error 'Assertion failed. ' + a + ' != ' + b,
+
+  abs(n)::
+    if !std.isNumber(n) then
+      error 'std.abs expected number, got ' + std.type(n)
+    else
+      if n > 0 then n else -n,
+
+  sign(n)::
+    if !std.isNumber(n) then
+      error 'std.sign expected number, got ' + std.type(n)
+    else
+      if n > 0 then
+        1
+      else if n < 0 then
+        -1
+      else 0,
+
+  max(a, b)::
+    if !std.isNumber(a) then
+      error 'std.max first param expected number, got ' + std.type(a)
+    else if !std.isNumber(b) then
+      error 'std.max second param expected number, got ' + std.type(b)
+    else
+      if a > b then a else b,
+
+  min(a, b)::
+    if !std.isNumber(a) then
+      error 'std.max first param expected number, got ' + std.type(a)
+    else if !std.isNumber(b) then
+      error 'std.max second param expected number, got ' + std.type(b)
+    else
+      if a < b then a else b,
+
+  clamp(x, minVal, maxVal)::
+    if x < minVal then minVal
+    else if x > maxVal then maxVal
+    else x,
+
+  flattenArrays(arrs)::
+    std.foldl(function(a, b) a + b, arrs, []),
+
+  manifestIni(ini)::
+    local body_lines(body) =
+      std.join([], [
+        local value_or_values = body[k];
+        if std.isArray(value_or_values) then
+          ['%s = %s' % [k, value] for value in value_or_values]
+        else
+          ['%s = %s' % [k, value_or_values]]
+
+        for k in std.objectFields(body)
+      ]);
+
+    local section_lines(sname, sbody) = ['[%s]' % [sname]] + body_lines(sbody),
+          main_body = if std.objectHas(ini, 'main') then body_lines(ini.main) else [],
+          all_sections = [
+      section_lines(k, ini.sections[k])
+      for k in std.objectFields(ini.sections)
+    ];
+    std.join('\n', main_body + std.flattenArrays(all_sections) + ['']),
+
+  escapeStringJson(str_)::
+    local str = std.toString(str_);
+    local trans(ch) =
+      if ch == '"' then
+        '\\"'
+      else if ch == '\\' then
+        '\\\\'
+      else if ch == '\b' then
+        '\\b'
+      else if ch == '\f' then
+        '\\f'
+      else if ch == '\n' then
+        '\\n'
+      else if ch == '\r' then
+        '\\r'
+      else if ch == '\t' then
+        '\\t'
+      else
+        local cp = std.codepoint(ch);
+        if cp < 32 || (cp >= 127 && cp <= 159) then
+          '\\u%04x' % [cp]
+        else
+          ch;
+    '"%s"' % std.join('', [trans(ch) for ch in std.stringChars(str)]),
+
+  escapeStringPython(str)::
+    std.escapeStringJson(str),
+
+  escapeStringBash(str_)::
+    local str = std.toString(str_);
+    local trans(ch) =
+      if ch == "'" then
+        "'\"'\"'"
+      else
+        ch;
+    "'%s'" % std.join('', [trans(ch) for ch in std.stringChars(str)]),
+
+  escapeStringDollars(str_)::
+    local str = std.toString(str_);
+    local trans(ch) =
+      if ch == '$' then
+        '$$'
+      else
+        ch;
+    std.foldl(function(a, b) a + trans(b), std.stringChars(str), ''),
+
+  manifestJson(value):: std.manifestJsonEx(value, '    '),
+
+  manifestJsonEx(value, indent)::
+    local aux(v, path, cindent) =
+      if v == true then
+        'true'
+      else if v == false then
+        'false'
+      else if v == null then
+        'null'
+      else if std.isNumber(v) then
+        '' + v
+      else if std.isString(v) then
+        std.escapeStringJson(v)
+      else if std.isFunction(v) then
+        error 'Tried to manifest function at ' + path
+      else if std.isArray(v) then
+        local range = std.range(0, std.length(v) - 1);
+        local new_indent = cindent + indent;
+        local lines = ['[\n']
+                      + std.join([',\n'],
+                                 [
+                                   [new_indent + aux(v[i], path + [i], new_indent)]
+                                   for i in range
+                                 ])
+                      + ['\n' + cindent + ']'];
+        std.join('', lines)
+      else if std.isObject(v) then
+        local lines = ['{\n']
+                      + std.join([',\n'],
+                                 [
+                                   [cindent + indent + std.escapeStringJson(k) + ': '
+                                    + aux(v[k], path + [k], cindent + indent)]
+                                   for k in std.objectFields(v)
+                                 ])
+                      + ['\n' + cindent + '}'];
+        std.join('', lines);
+    aux(value, [], ''),
+
+  manifestYamlDoc(value, indent_array_in_object=false)::
+    local aux(v, path, cindent) =
+      if v == true then
+        'true'
+      else if v == false then
+        'false'
+      else if v == null then
+        'null'
+      else if std.isNumber(v) then
+        '' + v
+      else if std.isString(v) then
+        local len = std.length(v);
+        if len == 0 then
+          '""'
+        else if v[len - 1] == '\n' then
+          local split = std.split(v, '\n');
+          std.join('\n' + cindent + '  ', ['|'] + split[0:std.length(split) - 1])
+        else
+          std.escapeStringJson(v)
+      else if std.isFunction(v) then
+        error 'Tried to manifest function at ' + path
+      else if std.isArray(v) then
+        if std.length(v) == 0 then
+          '[]'
+        else
+          local params(value) =
+            if std.isArray(value) && std.length(value) > 0 then {
+              // While we could avoid the new line, it yields YAML that is
+              // hard to read, e.g.:
+              // - - - 1
+              //     - 2
+              //   - - 3
+              //     - 4
+              new_indent: cindent + '  ',
+              space: '\n' + self.new_indent,
+            } else if std.isObject(value) && std.length(value) > 0 then {
+              new_indent: cindent + '  ',
+              // In this case we can start on the same line as the - because the indentation
+              // matches up then.  The converse is not true, because fields are not always
+              // 1 character long.
+              space: ' ',
+            } else {
+              // In this case, new_indent is only used in the case of multi-line strings.
+              new_indent: cindent,
+              space: ' ',
+            };
+          local range = std.range(0, std.length(v) - 1);
+          local parts = [
+            '-' + param.space + aux(v[i], path + [i], param.new_indent)
+            for i in range
+            for param in [params(v[i])]
+          ];
+          std.join('\n' + cindent, parts)
+      else if std.isObject(v) then
+        if std.length(v) == 0 then
+          '{}'
+        else
+          local params(value) =
+            if std.isArray(value) && std.length(value) > 0 then {
+              // Not indenting allows e.g.
+              // ports:
+              // - 80
+              // instead of
+              // ports:
+              //   - 80
+              new_indent: if indent_array_in_object then cindent + '  ' else cindent,
+              space: '\n' + self.new_indent,
+            } else if std.isObject(value) && std.length(value) > 0 then {
+              new_indent: cindent + '  ',
+              space: '\n' + self.new_indent,
+            } else {
+              // In this case, new_indent is only used in the case of multi-line strings.
+              new_indent: cindent,
+              space: ' ',
+            };
+          local lines = [
+            std.escapeStringJson(k) + ':' + param.space + aux(v[k], path + [k], param.new_indent)
+            for k in std.objectFields(v)
+            for param in [params(v[k])]
+          ];
+          std.join('\n' + cindent, lines);
+    aux(value, [], ''),
+
+  manifestYamlStream(value, indent_array_in_object=false, c_document_end=true)::
+    if !std.isArray(value) then
+      error 'manifestYamlStream only takes arrays, got ' + std.type(value)
+    else
+      '---\n' + std.join(
+        '\n---\n', [std.manifestYamlDoc(e, indent_array_in_object) for e in value]
+      ) + if c_document_end then '\n...\n' else '\n',
+
+
+  manifestPython(v)::
+    if std.isObject(v) then
+      local fields = [
+        '%s: %s' % [std.escapeStringPython(k), std.manifestPython(v[k])]
+        for k in std.objectFields(v)
+      ];
+      '{%s}' % [std.join(', ', fields)]
+    else if std.isArray(v) then
+      '[%s]' % [std.join(', ', [std.manifestPython(v2) for v2 in v])]
+    else if std.isString(v) then
+      '%s' % [std.escapeStringPython(v)]
+    else if std.isFunction(v) then
+      error 'cannot manifest function'
+    else if std.isNumber(v) then
+      std.toString(v)
+    else if v == true then
+      'True'
+    else if v == false then
+      'False'
+    else if v == null then
+      'None',
+
+  manifestPythonVars(conf)::
+    local vars = ['%s = %s' % [k, std.manifestPython(conf[k])] for k in std.objectFields(conf)];
+    std.join('\n', vars + ['']),
+
+  manifestXmlJsonml(value)::
+    if !std.isArray(value) then
+      error 'Expected a JSONML value (an array), got %s' % std.type(value)
+    else
+      local aux(v) =
+        if std.isString(v) then
+          v
+        else
+          local tag = v[0];
+          local has_attrs = std.length(v) > 1 && std.isObject(v[1]);
+          local attrs = if has_attrs then v[1] else {};
+          local children = if has_attrs then v[2:] else v[1:];
+          local attrs_str =
+            std.join('', [' %s="%s"' % [k, attrs[k]] for k in std.objectFields(attrs)]);
+          std.deepJoin(['<', tag, attrs_str, '>', [aux(x) for x in children], '</', tag, '>']);
+
+      aux(value),
+
+  local base64_table = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/',
+  local base64_inv = { [base64_table[i]]: i for i in std.range(0, 63) },
+
+  base64(input)::
+    local bytes =
+      if std.isString(input) then
+        std.map(function(c) std.codepoint(c), input)
+      else
+        input;
+
+    local aux(arr, i, r) =
+      if i >= std.length(arr) then
+        r
+      else if i + 1 >= std.length(arr) then
+        local str =
+          // 6 MSB of i
+          base64_table[(arr[i] & 252) >> 2] +
+          // 2 LSB of i
+          base64_table[(arr[i] & 3) << 4] +
+          '==';
+        aux(arr, i + 3, r + str) tailstrict
+      else if i + 2 >= std.length(arr) then
+        local str =
+          // 6 MSB of i
+          base64_table[(arr[i] & 252) >> 2] +
+          // 2 LSB of i, 4 MSB of i+1
+          base64_table[(arr[i] & 3) << 4 | (arr[i + 1] & 240) >> 4] +
+          // 4 LSB of i+1
+          base64_table[(arr[i + 1] & 15) << 2] +
+          '=';
+        aux(arr, i + 3, r + str) tailstrict
+      else
+        local str =
+          // 6 MSB of i
+          base64_table[(arr[i] & 252) >> 2] +
+          // 2 LSB of i, 4 MSB of i+1
+          base64_table[(arr[i] & 3) << 4 | (arr[i + 1] & 240) >> 4] +
+          // 4 LSB of i+1, 2 MSB of i+2
+          base64_table[(arr[i + 1] & 15) << 2 | (arr[i + 2] & 192) >> 6] +
+          // 6 LSB of i+2
+          base64_table[(arr[i + 2] & 63)];
+        aux(arr, i + 3, r + str) tailstrict;
+
+    local sanity = std.foldl(function(r, a) r && (a < 256), bytes, true);
+    if !sanity then
+      error 'Can only base64 encode strings / arrays of single bytes.'
+    else
+      aux(bytes, 0, ''),
+
+
+  base64DecodeBytes(str)::
+    if std.length(str) % 4 != 0 then
+      error 'Not a base64 encoded string "%s"' % str
+    else
+      local aux(str, i, r) =
+        if i >= std.length(str) then
+          r
+        else
+          // all 6 bits of i, 2 MSB of i+1
+          local n1 = [base64_inv[str[i]] << 2 | (base64_inv[str[i + 1]] >> 4)];
+          // 4 LSB of i+1, 4MSB of i+2
+          local n2 =
+            if str[i + 2] == '=' then []
+            else [(base64_inv[str[i + 1]] & 15) << 4 | (base64_inv[str[i + 2]] >> 2)];
+          // 2 LSB of i+2, all 6 bits of i+3
+          local n3 =
+            if str[i + 3] == '=' then []
+            else [(base64_inv[str[i + 2]] & 3) << 6 | base64_inv[str[i + 3]]];
+          aux(str, i + 4, r + n1 + n2 + n3) tailstrict;
+      aux(str, 0, []),
+
+  base64Decode(str)::
+    local bytes = std.base64DecodeBytes(str);
+    std.join('', std.map(function(b) std.char(b), bytes)),
+
+  reverse(arr)::
+    local l = std.length(arr);
+    std.makeArray(l, function(i) arr[l - i - 1]),
+
+  // Merge-sort for long arrays and naive quicksort for shorter ones
+  sort(arr, keyF=id)::
+    local quickSort(arr, keyF=id) =
+      local l = std.length(arr);
+      if std.length(arr) <= 1 then
+        arr
+      else
+        local pos = 0;
+        local pivot = keyF(arr[pos]);
+        local rest = std.makeArray(l - 1, function(i) if i < pos then arr[i] else arr[i + 1]);
+        local left = std.filter(function(x) keyF(x) < pivot, rest);
+        local right = std.filter(function(x) keyF(x) >= pivot, rest);
+        quickSort(left, keyF) + [arr[pos]] + quickSort(right, keyF);
+
+    local merge(a, b) =
+      local la = std.length(a), lb = std.length(b);
+      local aux(i, j, prefix) =
+        if i == la then
+          prefix + b[j:]
+        else if j == lb then
+          prefix + a[i:]
+        else
+          if keyF(a[i]) <= keyF(b[j]) then
+            aux(i + 1, j, prefix + [a[i]]) tailstrict
+          else
+            aux(i, j + 1, prefix + [b[j]]) tailstrict;
+      aux(0, 0, []);
+
+    local l = std.length(arr);
+    if std.length(arr) <= 30 then
+      quickSort(arr, keyF=keyF)
+    else
+      local mid = std.floor(l / 2);
+      local left = arr[:mid], right = arr[mid:];
+      merge(std.sort(left, keyF=keyF), std.sort(right, keyF=keyF)),
+
+  uniq(arr, keyF=id)::
+    local f(a, b) =
+      if std.length(a) == 0 then
+        [b]
+      else if keyF(a[std.length(a) - 1]) == keyF(b) then
+        a
+      else
+        a + [b];
+    std.foldl(f, arr, []),
+
+  set(arr, keyF=id)::
+    std.uniq(std.sort(arr, keyF), keyF),
+
+  setMember(x, arr, keyF=id)::
+    // TODO(dcunnin): Binary chop for O(log n) complexity
+    std.length(std.setInter([x], arr, keyF)) > 0,
+
+  setUnion(a, b, keyF=id)::
+    // NOTE: order matters, values in `a` win
+    local aux(a, b, i, j, acc) =
+      if i >= std.length(a) then
+        acc + b[j:]
+      else if j >= std.length(b) then
+        acc + a[i:]
+      else
+        local ak = keyF(a[i]);
+        local bk = keyF(b[j]);
+        if ak == bk then
+          aux(a, b, i + 1, j + 1, acc + [a[i]]) tailstrict
+        else if ak < bk then
+          aux(a, b, i + 1, j, acc + [a[i]]) tailstrict
+        else
+          aux(a, b, i, j + 1, acc + [b[j]]) tailstrict;
+    aux(a, b, 0, 0, []),
+
+  setInter(a, b, keyF=id)::
+    local aux(a, b, i, j, acc) =
+      if i >= std.length(a) || j >= std.length(b) then
+        acc
+      else
+        if keyF(a[i]) == keyF(b[j]) then
+          aux(a, b, i + 1, j + 1, acc + [a[i]]) tailstrict
+        else if keyF(a[i]) < keyF(b[j]) then
+          aux(a, b, i + 1, j, acc) tailstrict
+        else
+          aux(a, b, i, j + 1, acc) tailstrict;
+    aux(a, b, 0, 0, []) tailstrict,
+
+  setDiff(a, b, keyF=id)::
+    local aux(a, b, i, j, acc) =
+      if i >= std.length(a) then
+        acc
+      else if j >= std.length(b) then
+        acc + a[i:]
+      else
+        if keyF(a[i]) == keyF(b[j]) then
+          aux(a, b, i + 1, j + 1, acc) tailstrict
+        else if keyF(a[i]) < keyF(b[j]) then
+          aux(a, b, i + 1, j, acc + [a[i]]) tailstrict
+        else
+          aux(a, b, i, j + 1, acc) tailstrict;
+    aux(a, b, 0, 0, []) tailstrict,
+
+  mergePatch(target, patch)::
+    if std.isObject(patch) then
+      local target_object =
+        if std.isObject(target) then target else {};
+
+      local target_fields =
+        if std.isObject(target_object) then std.objectFields(target_object) else [];
+
+      local null_fields = [k for k in std.objectFields(patch) if patch[k] == null];
+      local both_fields = std.setUnion(target_fields, std.objectFields(patch));
+
+      {
+        [k]:
+          if !std.objectHas(patch, k) then
+            target_object[k]
+          else if !std.objectHas(target_object, k) then
+            std.mergePatch(null, patch[k]) tailstrict
+          else
+            std.mergePatch(target_object[k], patch[k]) tailstrict
+        for k in std.setDiff(both_fields, null_fields)
+      }
+    else
+      patch,
+
+  objectFields(o)::
+    std.objectFieldsEx(o, false),
+
+  objectFieldsAll(o)::
+    std.objectFieldsEx(o, true),
+
+  objectHas(o, f)::
+    std.objectHasEx(o, f, false),
+
+  objectHasAll(o, f)::
+    std.objectHasEx(o, f, true),
+
+  equals(a, b)::
+    local ta = std.type(a);
+    local tb = std.type(b);
+    if !std.primitiveEquals(ta, tb) then
+      false
+    else
+      if std.primitiveEquals(ta, 'array') then
+        local la = std.length(a);
+        if !std.primitiveEquals(la, std.length(b)) then
+          false
+        else
+          local aux(a, b, i) =
+            if i >= la then
+              true
+            else if a[i] != b[i] then
+              false
+            else
+              aux(a, b, i + 1) tailstrict;
+          aux(a, b, 0)
+      else if std.primitiveEquals(ta, 'object') then
+        local fields = std.objectFields(a);
+        local lfields = std.length(fields);
+        if fields != std.objectFields(b) then
+          false
+        else
+          local aux(a, b, i) =
+            if i >= lfields then
+              true
+            else if local f = fields[i]; a[f] != b[f] then
+              false
+            else
+              aux(a, b, i + 1) tailstrict;
+          aux(a, b, 0)
+      else
+        std.primitiveEquals(a, b),
+
+
+  resolvePath(f, r)::
+    local arr = std.split(f, '/');
+    std.join('/', std.makeArray(std.length(arr) - 1, function(i) arr[i]) + [r]),
+
+  prune(a)::
+    local isContent(b) =
+      if b == null then
+        false
+      else if std.isArray(b) then
+        std.length(b) > 0
+      else if std.isObject(b) then
+        std.length(b) > 0
+      else
+        true;
+    if std.isArray(a) then
+      [std.prune(x) for x in a if isContent($.prune(x))]
+    else if std.isObject(a) then {
+      [x]: $.prune(a[x])
+      for x in std.objectFields(a)
+      if isContent(std.prune(a[x]))
+    } else
+      a,
+
+  findSubstr(pat, str)::
+    if !std.isString(pat) then
+      error 'findSubstr first parameter should be a string, got ' + std.type(pat)
+    else if !std.isString(str) then
+      error 'findSubstr second parameter should be a string, got ' + std.type(str)
+    else
+      local pat_len = std.length(pat);
+      local str_len = std.length(str);
+      if pat_len == 0 || str_len == 0 || pat_len > str_len then
+        []
+      else
+        std.filter(function(i) str[i:i + pat_len] == pat, std.range(0, str_len - pat_len)),
+
+  find(value, arr)::
+    if !std.isArray(arr) then
+      error 'find second parameter should be an array, got ' + std.type(arr)
+    else
+      std.filter(function(i) arr[i] == value, std.range(0, std.length(arr) - 1)),
+}