From 02b7991d635925e8c3d65571060ae13dbc231ddf Mon Sep 17 00:00:00 2001
From: Yaroslav Bolyukin <iam@lach.pw>
Date: Mon, 12 Jul 2021 17:20:24 +0000
Subject: [PATCH] perf: make std.substr builtin


---
--- a/crates/jrsonnet-evaluator/src/builtin/mod.rs
+++ b/crates/jrsonnet-evaluator/src/builtin/mod.rs
@@ -81,6 +81,7 @@
 			("objectFieldsEx".into(), builtin_object_fields_ex),
 			("objectHasEx".into(), builtin_object_has_ex),
 			("slice".into(), builtin_slice),
+			("substr".into(), builtin_substr),
 			("primitiveEquals".into(), builtin_primitive_equals),
 			("equals".into(), builtin_equals),
 			("modulo".into(), builtin_modulo),
@@ -241,6 +242,17 @@
 	})
 }
 
+fn builtin_substr(context: Context, _loc: Option<&ExprLocation>, args: &ArgsDesc) -> Result<Val> {
+	parse_args!(context, "substr", args, 3, [
+		0, str: ty!(string) => Val::Str;
+		1, from: ty!(BoundedNumber<(Some(0.0)), (None)>) => Val::Num;
+		2, len: ty!(BoundedNumber<(Some(0.0)), (None)>) => Val::Num;
+	], {
+		let out: String = str.chars().skip(from as usize).take(len as usize).collect();
+		Ok(Val::Str(out.into()))
+	})
+}
+
 fn builtin_primitive_equals(
 	context: Context,
 	_loc: Option<&ExprLocation>,
--- a/crates/jrsonnet-stdlib/src/std.jsonnet
+++ b/crates/jrsonnet-stdlib/src/std.jsonnet
@@ -48,12 +48,7 @@
   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])),
+  substr:: $intrinsic(substr),
 
   startsWith(a, b)::
     if std.length(a) < std.length(b) then

-- 
gitstuff