From 31dfb91f8ba375b1e36be855f8ec823de8da5c2c Mon Sep 17 00:00:00 2001
From: Лач <iam@lach.pw>
Date: Sat, 16 May 2020 04:33:52 +0000
Subject: [PATCH] chore(parser): initial parser commit


---
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+/target
--- /dev/null
+++ b/Cargo.lock
@@ -0,0 +1,59 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "jsonnet-parser"
+version = "0.1.0"
+dependencies = [
+ "peg",
+]
+
+[[package]]
+name = "peg"
+version = "0.6.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9075875c14bb21f25f11cad4b6ad2e4dd443b8fb83900b2fbdd6ebd744b82e97"
+dependencies = [
+ "peg-macros",
+ "peg-runtime",
+]
+
+[[package]]
+name = "peg-macros"
+version = "0.6.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c24c165fd39e995246140cc78df55c56c6733ba87e6658cb3e197b8856c62852"
+dependencies = [
+ "peg-runtime",
+ "proc-macro2",
+ "quote",
+]
+
+[[package]]
+name = "peg-runtime"
+version = "0.6.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0c1a2897e69d986c7986747ebad425cf03746ec5e3e09bb3b2600f91301ba864"
+
+[[package]]
+name = "proc-macro2"
+version = "1.0.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8872cf6f48eee44265156c111456a700ab3483686b3f96df4cf5481c89157319"
+dependencies = [
+ "unicode-xid",
+]
+
+[[package]]
+name = "quote"
+version = "1.0.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "42934bc9c8ab0d3b273a16d8551c8f0fcff46be73276ca083ec2414c15c4ba5e"
+dependencies = [
+ "proc-macro2",
+]
+
+[[package]]
+name = "unicode-xid"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "826e7639553986605ec5979c7dd957c7895e93eabed50ab2ffa7f6128a75097c"
--- /dev/null
+++ b/Cargo.toml
@@ -0,0 +1,2 @@
+[workspace]
+members = ["crates/jsonnet-parser"]
--- /dev/null
+++ b/crates/jsonnet-parser/Cargo.toml
@@ -0,0 +1,10 @@
+[package]
+name = "jsonnet-parser"
+version = "0.1.0"
+authors = ["Лач <iam@lach.pw>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+peg = "0.6.2"
--- /dev/null
+++ b/crates/jsonnet-parser/src/expr.rs
@@ -0,0 +1,206 @@
+#[derive(Debug, Clone, PartialEq)]
+pub enum FieldName {
+	/// {fixed: 2}
+	Fixed(String),
+	/// {["dyn"+"amic"]: 3}
+	Dyn(Box<Expr>),
+}
+
+#[derive(Debug, Clone, PartialEq)]
+pub enum Visibility {
+	/// :
+	Normal,
+	/// ::
+	Hidden,
+	/// :::
+	Unhide,
+}
+
+#[derive(Debug, Clone, PartialEq)]
+pub struct AssertStmt(pub Box<Expr>, pub Option<Box<Expr>>);
+
+#[derive(Debug, Clone, PartialEq)]
+pub enum FieldMember {
+	Value {
+		name: FieldName,
+		plus: bool,
+		visibility: Visibility,
+		value: Expr,
+	},
+	Function {
+		name: FieldName,
+		params: Params,
+		visibility: Visibility,
+		value: Expr,
+	},
+}
+
+#[derive(Debug, Clone, PartialEq)]
+pub enum Member {
+	Field(FieldMember),
+	BindStmt(Bind),
+	AssertStmt(AssertStmt),
+}
+
+#[derive(Debug, Clone, PartialEq)]
+pub enum UnaryOp {
+	Plus,
+	Minus,
+	BitNot,
+	Not,
+}
+
+#[derive(Debug, Clone, PartialEq)]
+pub enum BinaryOp {
+	Mul,
+	Div,
+	Mod,
+
+	Add,
+	Sub,
+
+	Lhs,
+	Rhs,
+
+	Lt,
+	Gt,
+	Lte,
+	Gte,
+
+	In,
+
+	Eq,
+	Ne,
+
+	BitAnd,
+	BitOr,
+	And,
+	Or,
+
+	BitXor,
+}
+
+#[derive(Debug, Clone, PartialEq)]
+pub enum Param {
+	Positional(String),
+	Named(String, Box<Expr>),
+}
+
+#[derive(Debug, Clone, PartialEq)]
+pub struct Params(pub Vec<Param>);
+
+#[derive(Debug, Clone, PartialEq)]
+pub enum Arg {
+	Positional(Box<Expr>),
+	Named(String, Box<Expr>),
+}
+
+#[derive(Debug, Clone, PartialEq)]
+pub struct Args(pub Vec<Arg>);
+
+#[derive(Debug, Clone, PartialEq)]
+pub enum Bind {
+	Value(String, Box<Expr>),
+	Function(String, Params, Box<Expr>),
+}
+
+#[derive(Debug, Clone, PartialEq)]
+pub struct IfSpec(pub Box<Expr>);
+#[derive(Debug, Clone, PartialEq)]
+pub struct ForSpec(pub String, pub Vec<IfSpec>);
+
+#[derive(Debug, Clone, PartialEq)]
+pub enum CompSpec {
+	IfSpec(IfSpec),
+	ForSpec(ForSpec),
+}
+
+#[derive(Debug, Clone, PartialEq)]
+pub enum ObjBody {
+	MemberList(Vec<Member>),
+	ObjComp {
+		pre_locals: Vec<Bind>,
+		key: Box<Expr>,
+		value: Box<Expr>,
+		post_locals: Vec<Bind>,
+		first: ForSpec,
+		rest: Vec<CompSpec>,
+	},
+}
+
+#[derive(Debug, Clone, PartialEq)]
+pub enum Literal {
+	Null,
+	True,
+	False,
+	This,
+	Super,
+	Dollar,
+}
+
+/// Syntax base
+#[derive(Debug, Clone, PartialEq)]
+pub enum Expr {
+	/// Plain value: null/true/false
+	Literal(Literal),
+
+	/// String value: "hello"
+	Str(String),
+	/// Number: 1, 2.0, 2e+20
+	Num(f64),
+	/// Variable name: test
+	Var(String),
+
+	/// Array of expressions: [1, 2, "Hello"]
+	Arr(Vec<Expr>),
+	/// Array comprehension:
+	/// ```jsonnet
+	///  ingredients: [
+	///    { kind: kind, qty: 4 / 3 }
+	///    for kind in [
+	///      'Honey Syrup',
+	///      'Lemon Juice',
+	///      'Farmers Gin',
+	///    ]
+	///  ],
+	/// ```
+	ArrComp(Box<Expr>, Vec<ForSpec>),
+
+	/// Object: {a: 2}
+	Obj(ObjBody),
+	/// Object extension: var1 {b: 2}
+	ObjExtend(Box<Expr>, ObjBody),
+
+	/// (obj)
+	Parened(Box<Expr>),
+
+	Params(Params),
+	Args(Args),
+
+	UnaryOp(UnaryOp, Box<Expr>),
+	BinaryOp(Box<Expr>, BinaryOp, Box<Expr>),
+	AssertExpr(AssertStmt, Box<Expr>),
+	LocalExpr(Vec<Bind>, Box<Expr>),
+
+	Bind(Bind),
+	Import(String),
+	ImportStr(String),
+	Error(Box<Expr>),
+	Apply(Box<Expr>, Args),
+	Select(Box<Expr>, String),
+	Index(Box<Expr>, Box<Expr>),
+	Slice {
+		value: Box<Expr>,
+		start: Option<Box<Expr>>,
+		end: Option<Box<Expr>>,
+		step: Option<Box<Expr>>,
+	},
+	Function(Params, Box<Expr>),
+	IfElse {
+		cond: IfSpec,
+		cond_then: Box<Expr>,
+		cond_else: Option<Box<Expr>>,
+	},
+	IfSpec(IfSpec),
+	ForSpec(ForSpec),
+}
--- /dev/null
+++ b/crates/jsonnet-parser/src/lib.rs
@@ -0,0 +1,208 @@
+use peg::parser;
+
+pub mod expr;
+use expr::{Expr, Literal};
+
+enum Suffix {
+	String(String),
+	Expression(Expr),
+	Apply(expr::Args),
+}
+
+parser! {
+	grammar jsonnet_parser() for str {
+		rule delimiter() = quiet!{__() "," __()} / expected!("<elements delimiter>")
+		rule _() = quiet!{[' ' | '\n' | '\t']+} / expected!("<whitespace>")
+		rule __() = quiet!{[' ' | '\n' | '\t']*}
+		rule alpha() -> char = c:$(['_' | 'a'..='z' | 'A'..='Z']) {c.chars().nth(0).unwrap()}
+		rule digit() -> char = d:$(['0'..='9']) {d.chars().nth(0).unwrap()}
+		rule int() -> u32 = a:$(digit()+) { a.parse().unwrap() }
+		rule number() -> f64 = quiet!{a:$((['-'|'+'])? int() ("." int())? (['e'|'E'] (s:['+'|'-'])? int())?) { a.parse().unwrap() }} / expected!("<number>")
+		rule id() -> String = quiet!{ !("local" / "super" / "self" / "true" / "false" / "null" / "$" / "if" / "then" / "else") s:$(alpha() (alpha() / digit())*) {s.to_owned()}} / expected!("<identifier>")
+
+		pub rule positional_param() -> expr::Param = name:id() {expr::Param::Positional(name)}
+		pub rule named_param() -> expr::Param = name:id() __() "=" __() expr:boxed_expr() {expr::Param::Named(name, expr)}
+		pub rule params() -> expr::Params
+			= positionals:(positional_param() ** delimiter()) delimiter() named:(named_param() ** delimiter()) {
+				expr::Params([&positionals[..], &named[..]].concat())
+			}
+			/ named:(named_param() ** delimiter()) {expr::Params(named)}
+			/ positionals:(positional_param() ** delimiter()) {expr::Params(positionals)}
+			/ {expr::Params(Vec::new())}
+
+		pub rule positional_arg() -> expr::Arg = quiet!{name:boxed_expr() {expr::Arg::Positional(name)}}/expected!("<positional arg>")
+		pub rule named_arg() -> expr::Arg = quiet!{name:id() __() "=" __() expr:boxed_expr() {expr::Arg::Named(name, expr)}}/expected!("<named arg>")
+		pub rule args() -> expr::Args
+			= positionals:(positional_arg() ** delimiter()) delimiter() named:(named_arg() ** delimiter()) {
+				expr::Args([&positionals[..], &named[..]].concat())
+			}
+			/ named:(named_arg() ** delimiter()) {expr::Args(named)}
+			/ positionals:(positional_arg() ** delimiter()) {expr::Args(positionals)}
+			/ {expr::Args(Vec::new())}
+
+		pub rule bind() -> expr::Bind
+			= name:id() __() "=" __() expr:boxed_expr() {expr::Bind::Value(name, expr)}
+			/ name:id() __() "(" __() params:params() __() ")" __() "=" __() expr:boxed_expr() {expr::Bind::Function(name, params, expr)}
+		pub rule assertion() -> expr::AssertStmt = "assert" _() cond:boxed_expr() msg:(__() ":" __() e:boxed_expr() {e})? { expr::AssertStmt(cond, msg) }
+		pub rule string() -> String
+			= "\"" str:$((!['"'][_])+) "\"" {str.to_owned()}
+			/ "'" str:$((!['\''][_])+) "'" {str.to_owned()}
+		pub rule field_name() -> expr::FieldName
+			= name:id() {expr::FieldName::Fixed(name)}
+			/ name:string() {expr::FieldName::Fixed(name)}
+			/ "[" __() expr:boxed_expr() __() "]" {expr::FieldName::Dyn(expr)}
+		pub rule visibility() -> expr::Visibility
+			= ":::" {expr::Visibility::Unhide}
+			/ "::" {expr::Visibility::Hidden}
+			/ ":" {expr::Visibility::Normal}
+		pub rule field() -> expr::FieldMember
+			= name:field_name() __() plus:"+"? __() visibility:visibility() __() value:expr() {expr::FieldMember::Value{
+				name,
+				plus: plus.is_some(),
+				visibility,
+				value,
+			}}
+			/ name:field_name() __() "(" __() params:params() __() ")" __() visibility:visibility() __() value:expr() {expr::FieldMember::Function{
+				name,
+				params,
+				visibility,
+				value,
+			}}
+		pub rule member() -> expr::Member
+			= "local" _() bind:bind() {expr::Member::BindStmt(bind)}
+			/ assertion:assertion() {expr::Member::AssertStmt(assertion)}
+			/ field:field() {expr::Member::Field(field)}
+		pub rule obj_body() -> expr::ObjBody = members:(member() ** delimiter()) delimiter()? {expr::ObjBody::MemberList(members)}
+		pub rule ifspec() -> expr::IfSpec = "if" _() expr:boxed_expr() {expr::IfSpec(expr)}
+		pub rule forspec() -> expr::ForSpec = "for" _() id:id() _() "in" _() ifs:ifspec()* {expr::ForSpec(id, ifs)}
+		pub rule bind_expr() -> Expr = bind:bind() {Expr::Bind(bind)}
+		pub rule local_expr() -> Expr = "local" _() binds:(bind() ** delimiter()) __() ";" __() expr:boxed_expr() { Expr::LocalExpr(binds, expr) }
+		pub rule string_expr() -> Expr = s:string() {Expr::Str(s)}
+		pub rule parened_expr() -> Expr = "(" e:boxed_expr() ")" {Expr::Parened(e)}
+		pub rule obj_expr() -> Expr = "{" __() body:obj_body() __() "}" {Expr::Obj(body)}
+		pub rule array_expr() -> Expr = "[" __() elems:(expr() ** delimiter()) __() delimiter()? "]" {Expr::Arr(elems)}
+		pub rule array_comp_expr() -> Expr = "[" __() expr:boxed_expr() delimiter()? fors:forspec()+ __() "]" {Expr::ArrComp(expr, fors)}
+		pub rule index_expr() -> Expr
+			= val:boxed_expr() "." idx:id() {Expr::Index(val, Box::new(Expr::Str(idx)))}
+			/ val:boxed_expr() "[" key:boxed_expr() "]" {Expr::Index(val, key)}
+		pub rule slice_expr() -> Expr
+			= value:boxed_expr() "[" start:boxed_expr()? ":" pair:(end:boxed_expr()? step:(":" e:boxed_expr() {e})? {(end, step)})? "]" {
+			if let Some((end, step)) = pair {
+				Expr::Slice { value, start, end, step }
+			}else{
+				Expr::Slice{ value, start, end: None, step: None }
+			}
+		}
+		pub rule number_expr() -> Expr = n:number() { expr::Expr::Num(n) }
+		pub rule var_expr() -> Expr = n:id() { expr::Expr::Var(n) }
+		pub rule if_then_else_expr() -> Expr = cond:ifspec() _() "then" _() cond_then:boxed_expr() cond_else:(_() "else" _() e:boxed_expr() {e})? {Expr::IfElse{
+			cond,
+			cond_then,
+			cond_else,
+		}}
+		pub rule expr_basic() -> Expr
+			= "null" {Expr::Literal(Literal::Null)}
+			/ "true" {Expr::Literal(Literal::True)} / "false" {Expr::Literal(Literal::False)}
+			/ "self" {Expr::Literal(Literal::This)} / "$" {Expr::Literal(Literal::Dollar)}
+			/ "super" {Expr::Literal(Literal::Super)}
+
+			/ string_expr() / number_expr()
+			/ array_expr()
+			/ array_comp_expr()
+			/ obj_expr()
+			/ array_expr()
+			/ array_comp_expr()
+
+			/ var_expr()
+			/ if_then_else_expr()
+			/ local_expr()
+
+		rule expr_suffix() -> Suffix
+			= "." __() s:id() { Suffix::String(s) }
+			/ "[" __() s:expr() __() "]" { Suffix::Expression(s) }
+			/ "(" __() args:args() __() ")" { Suffix::Apply(args) }
+
+		rule expr() -> Expr
+			= a:precedence! {
+				a:(@) __() "||" __() b:@ {Expr::BinaryOp(Box::new(a), expr::BinaryOp::Or, Box::new(b))}
+				--
+				a:(@) __() "&&" __() b:@ {Expr::BinaryOp(Box::new(a), expr::BinaryOp::And, Box::new(b))}
+				--
+				a:(@) __() "|" __() b:@ {Expr::BinaryOp(Box::new(a), expr::BinaryOp::BitOr, Box::new(b))}
+				--
+				a:@ __() "^" __() b:(@) {Expr::BinaryOp(Box::new(a), expr::BinaryOp::BitXor, Box::new(b))}
+				--
+				a:(@) __() "&" __() b:@ {Expr::BinaryOp(Box::new(a), expr::BinaryOp::BitAnd, Box::new(b))}
+				--
+				a:(@) __() "==" __() b:@ {Expr::BinaryOp(Box::new(a), expr::BinaryOp::Eq, Box::new(b))}
+				a:(@) __() "!=" __() b:@ {Expr::BinaryOp(Box::new(a), expr::BinaryOp::Ne, Box::new(b))}
+				--
+				a:(@) __() "<" __() b:@ {Expr::BinaryOp(Box::new(a), expr::BinaryOp::Lt, Box::new(b))}
+				a:(@) __() ">" __() b:@ {Expr::BinaryOp(Box::new(a), expr::BinaryOp::Gt, Box::new(b))}
+				a:(@) __() "<=" __() b:@ {Expr::BinaryOp(Box::new(a), expr::BinaryOp::Lte, Box::new(b))}
+				a:(@) __() ">=" __() b:@ {Expr::BinaryOp(Box::new(a), expr::BinaryOp::Gte, Box::new(b))}
+				--
+				a:(@) __() "<<" __() b:@ {Expr::BinaryOp(Box::new(a), expr::BinaryOp::Lhs, Box::new(b))}
+				a:(@) __() ">>" __() b:@ {Expr::BinaryOp(Box::new(a), expr::BinaryOp::Rhs, Box::new(b))}
+				--
+				a:(@) __() "+" __() b:@ {Expr::BinaryOp(Box::new(a), expr::BinaryOp::Add, Box::new(b))}
+				a:(@) __() "-" __() b:@ {Expr::BinaryOp(Box::new(a), expr::BinaryOp::Sub, Box::new(b))}
+				--
+				a:(@) __() "*" __() b:@ {Expr::BinaryOp(Box::new(a), expr::BinaryOp::Mul, Box::new(b))}
+				a:(@) __() "/" __() b:@ {Expr::BinaryOp(Box::new(a), expr::BinaryOp::Div, Box::new(b))}
+				a:(@) __() "%" __() b:@ {Expr::BinaryOp(Box::new(a), expr::BinaryOp::Mod, Box::new(b))}
+				--
+				e:expr_basic() {e}
+				"(" __() e:expr_basic() __() ")" {Expr::Parened(Box::new(e))}
+			} suffixes:(__() suffix:expr_suffix() {suffix})* {
+				let mut cur = a;
+				for suffix in suffixes {
+					match suffix {
+						Suffix::String(index) => {
+							cur = Expr::Index(Box::new(cur), Box::new(Expr::Str(index)))
+						},
+						Suffix::Expression(index) => {
+							cur = Expr::Index(Box::new(cur), Box::new(index))
+						},
+						Suffix::Apply(args) => {
+							cur = Expr::Apply(Box::new(cur), args)
+						}
+					}
+				}
+				cur
+			}
+			/ e:expr_basic() {e}
+
+		pub rule boxed_expr() -> Box<Expr> = e:expr() {Box::new(e)}
+		pub rule jsonnet() -> Expr = __() e:expr() __() {e}
+	}
+}
+
+// TODO: impl FromStr from Expr
+pub fn parse(str: &str) -> Result<Expr, peg::error::ParseError<peg::str::LineCol>> {
+	jsonnet_parser::jsonnet(str)
+}
+
+#[cfg(test)]
+pub mod tests {
+	use super::{expr::*, parse};
+	#[test]
+	fn empty_object() {
+		assert_eq!(parse("{}").unwrap(), Expr::Obj(ObjBody::MemberList(vec![])),);
+	}
+	#[test]
+	fn basic_math() {
+		assert_eq!(
+			parse("2+2*2").unwrap(),
+			Expr::BinaryOp(
+				Box::new(Expr::Num(2.0)),
+				BinaryOp::Add,
+				Box::new(Expr::BinaryOp(
+					Box::new(Expr::Num(2.0)),
+					BinaryOp::Mul,
+					Box::new(Expr::Num(2.0))
+				))
+			)
+		);
+	}
+}

-- 
gitstuff