From 923d478b33660a008e52bf1ee6f811c12c7d8e2f Mon Sep 17 00:00:00 2001
From: elkowar <5300871+elkowar@users.noreply.github.com>
Date: Mon, 12 Jul 2021 16:45:16 +0200
Subject: [PATCH] Start implementing parser

---
 .gitignore                                  |  2 +
 Cargo.toml                                  | 28 ++++++
 build.rs                                    |  4 +
 rust-toolchain                              |  1 +
 rustfmt.toml                                | 14 +++
 src/ast.rs                                  | 94 +++++++++++++++++++++
 src/lib.rs                                  | 35 ++++++++
 src/parser.lalrpop                          | 57 +++++++++++++
 src/snapshots/simplexpr__tests__test-2.snap | 16 ++++
 src/snapshots/simplexpr__tests__test-3.snap | 34 ++++++++
 src/snapshots/simplexpr__tests__test-4.snap | 22 +++++
 src/snapshots/simplexpr__tests__test-5.snap | 24 ++++++
 src/snapshots/simplexpr__tests__test-6.snap | 30 +++++++
 src/snapshots/simplexpr__tests__test-7.snap | 30 +++++++
 src/snapshots/simplexpr__tests__test-8.snap | 18 ++++
 src/snapshots/simplexpr__tests__test.snap   | 10 +++
 16 files changed, 419 insertions(+)
 create mode 100644 .gitignore
 create mode 100644 Cargo.toml
 create mode 100644 build.rs
 create mode 100644 rust-toolchain
 create mode 100644 rustfmt.toml
 create mode 100644 src/ast.rs
 create mode 100644 src/lib.rs
 create mode 100644 src/parser.lalrpop
 create mode 100644 src/snapshots/simplexpr__tests__test-2.snap
 create mode 100644 src/snapshots/simplexpr__tests__test-3.snap
 create mode 100644 src/snapshots/simplexpr__tests__test-4.snap
 create mode 100644 src/snapshots/simplexpr__tests__test-5.snap
 create mode 100644 src/snapshots/simplexpr__tests__test-6.snap
 create mode 100644 src/snapshots/simplexpr__tests__test-7.snap
 create mode 100644 src/snapshots/simplexpr__tests__test-8.snap
 create mode 100644 src/snapshots/simplexpr__tests__test.snap

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..96ef6c0
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+/target
+Cargo.lock
diff --git a/Cargo.toml b/Cargo.toml
new file mode 100644
index 0000000..87e69fd
--- /dev/null
+++ b/Cargo.toml
@@ -0,0 +1,28 @@
+[package]
+name = "simplexpr"
+version = "0.1.0"
+edition = "2018"
+authors = ["elkowar <5300871+elkowar@users.noreply.github.com>"]
+
+
+build = "build.rs"
+
+[dependencies]
+lalrpop-util = "0.19.5"
+regex = "1"
+itertools = "0.10"
+thiserror = "1.0"
+maplit = "1.0"
+codespan-reporting = "0.11"
+logos = "0.12"
+
+serde = {version = "1.0", features = ["derive"]}
+serde_json = "1.0"
+
+
+
+[build-dependencies]
+lalrpop = "0.19.5"
+
+[dev-dependencies]
+insta = "1.7"
diff --git a/build.rs b/build.rs
new file mode 100644
index 0000000..57684be
--- /dev/null
+++ b/build.rs
@@ -0,0 +1,4 @@
+extern crate lalrpop;
+fn main() {
+    lalrpop::process_root().unwrap();
+}
diff --git a/rust-toolchain b/rust-toolchain
new file mode 100644
index 0000000..bf867e0
--- /dev/null
+++ b/rust-toolchain
@@ -0,0 +1 @@
+nightly
diff --git a/rustfmt.toml b/rustfmt.toml
new file mode 100644
index 0000000..edce9c8
--- /dev/null
+++ b/rustfmt.toml
@@ -0,0 +1,14 @@
+unstable_features = true
+fn_single_line = false
+max_width = 130
+reorder_impl_items = true
+merge_imports = true
+normalize_comments = true
+use_field_init_shorthand = true
+#wrap_comments = true
+combine_control_expr = false
+condense_wildcard_suffixes = true
+format_code_in_doc_comments = true
+format_macro_matchers = true
+format_strings = true
+use_small_heuristics = "Max"
diff --git a/src/ast.rs b/src/ast.rs
new file mode 100644
index 0000000..0bb2684
--- /dev/null
+++ b/src/ast.rs
@@ -0,0 +1,94 @@
+use itertools::Itertools;
+use serde::{Deserialize, Serialize};
+
+#[derive(Eq, PartialEq, Clone, Copy)]
+pub struct Span(pub usize, pub usize, pub usize);
+
+impl std::fmt::Display for Span {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}..{}", self.0, self.1)
+    }
+}
+
+impl std::fmt::Debug for Span {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}..{}", self.0, self.1)
+    }
+}
+
+#[derive(Clone, PartialEq, Serialize, Deserialize, Debug)]
+pub enum BinOp {
+    Plus,
+    Minus,
+    Times,
+    Div,
+    Mod,
+    Equals,
+    NotEquals,
+    And,
+    Or,
+    GT,
+    LT,
+    Elvis,
+    RegexMatch,
+}
+
+impl std::fmt::Display for BinOp {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            BinOp::Plus => write!(f, "+"),
+            BinOp::Minus => write!(f, "-"),
+            BinOp::Times => write!(f, "*"),
+            BinOp::Div => write!(f, "/"),
+            BinOp::Mod => write!(f, "%"),
+            BinOp::Equals => write!(f, "=="),
+            BinOp::NotEquals => write!(f, "!="),
+            BinOp::And => write!(f, "&&"),
+            BinOp::Or => write!(f, "||"),
+            BinOp::GT => write!(f, ">"),
+            BinOp::LT => write!(f, "<"),
+            BinOp::Elvis => write!(f, "?:"),
+            BinOp::RegexMatch => write!(f, "=~"),
+        }
+    }
+}
+
+#[derive(Clone, PartialEq, Serialize, Deserialize, Debug)]
+pub enum UnaryOp {
+    Not,
+}
+
+impl std::fmt::Display for UnaryOp {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            UnaryOp::Not => write!(f, "!"),
+        }
+    }
+}
+
+#[derive(Clone, PartialEq, Serialize, Deserialize, Debug)]
+pub enum SimplExpr {
+    Literal(String),
+    VarRef(String),
+    BinOp(Box<SimplExpr>, BinOp, Box<SimplExpr>),
+    UnaryOp(UnaryOp, Box<SimplExpr>),
+    IfElse(Box<SimplExpr>, Box<SimplExpr>, Box<SimplExpr>),
+    JsonAccess(Box<SimplExpr>, Box<SimplExpr>),
+    FunctionCall(String, Vec<SimplExpr>),
+}
+
+impl std::fmt::Display for SimplExpr {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            SimplExpr::VarRef(x) => write!(f, "{}", x),
+            SimplExpr::Literal(x) => write!(f, "\"{}\"", x),
+            SimplExpr::BinOp(l, op, r) => write!(f, "({} {} {})", l, op, r),
+            SimplExpr::UnaryOp(op, x) => write!(f, "{}{}", op, x),
+            SimplExpr::IfElse(a, b, c) => write!(f, "(if {} then {} else {})", a, b, c),
+            SimplExpr::JsonAccess(value, index) => write!(f, "{}[{}]", value, index),
+            SimplExpr::FunctionCall(function_name, args) => {
+                write!(f, "{}({})", function_name, args.iter().join(", "))
+            }
+        }
+    }
+}
diff --git a/src/lib.rs b/src/lib.rs
new file mode 100644
index 0000000..1636430
--- /dev/null
+++ b/src/lib.rs
@@ -0,0 +1,35 @@
+pub mod ast;
+use lalrpop_util::lalrpop_mod;
+
+lalrpop_mod!(pub parser);
+
+macro_rules! test_parser {
+    ($($text:literal),*) => {{
+        let p = crate::parser::ExprParser::new();
+        //use crate::lexer::Lexer;
+
+        ::insta::with_settings!({sort_maps => true}, {
+            $(
+                ::insta::assert_debug_snapshot!(p.parse($text));
+            )*
+        });
+    }}
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn test() {
+        test_parser!(
+            "1",
+            "2 + 5",
+            "2 * 5 + 1 * 1 + 3",
+            "(1 + 2) * 2",
+            "1 + true ? 2 : 5",
+            "1 + true ? 2 : 5 + 2",
+            "1 + (true ? 2 : 5) + 2",
+            "foo(1, 2)",
+            "! false || ! true"
+        );
+    }
+}
diff --git a/src/parser.lalrpop b/src/parser.lalrpop
new file mode 100644
index 0000000..2db6bf0
--- /dev/null
+++ b/src/parser.lalrpop
@@ -0,0 +1,57 @@
+
+use crate::ast::{SimplExpr, Span, BinOp, UnaryOp};
+
+grammar;
+
+Comma<T>: Vec<T> = {
+    <mut v:(<T> ",")*> <e:T?> => match e {
+        None => v,
+        Some(e) => {
+            v.push(e);
+            v
+        }
+    }
+};
+
+pub Expr: SimplExpr = {
+  #[precedence(level="0")]
+  "true" => SimplExpr::Literal("true".to_string()),
+  "false" => SimplExpr::Literal("false".to_string()),
+  <Number>,
+  "(" <ExprReset> ")",
+  <ident:Ident> "(" <args: Comma<ExprReset>> ")" => SimplExpr::FunctionCall(ident, args),
+
+
+  #[precedence(level="1")] #[assoc(side="left")]
+  "!" <Expr> => SimplExpr::UnaryOp(UnaryOp::Not, Box::new(<>))
+
+
+  #[precedence(level="2")] #[assoc(side="left")]
+  <l:Expr> "*" <r:Expr> => SimplExpr::BinOp(Box::new(l), BinOp::Times, Box::new(r)),
+  <l:Expr> "/" <r:Expr> => SimplExpr::BinOp(Box::new(l), BinOp::Div, Box::new(r)),
+  <l:Expr> "%" <r:Expr> => SimplExpr::BinOp(Box::new(l), BinOp::Mod, Box::new(r)),
+
+  #[precedence(level="3")] #[assoc(side="left")]
+  <l:Expr> "+" <r:Expr> => SimplExpr::BinOp(Box::new(l), BinOp::Plus, Box::new(r)),
+  <l:Expr> "-" <r:Expr> => SimplExpr::BinOp(Box::new(l), BinOp::Minus, Box::new(r)),
+
+  #[precedence(level="4")] #[assoc(side="left")]
+  <l:Expr> "==" <r:Expr> => SimplExpr::BinOp(Box::new(l), BinOp::Equals, Box::new(r)),
+  <l:Expr> "!=" <r:Expr> => SimplExpr::BinOp(Box::new(l), BinOp::NotEquals, Box::new(r)),
+  <l:Expr> "<"  <r:Expr> => SimplExpr::BinOp(Box::new(l), BinOp::GT, Box::new(r)),
+  <l:Expr> ">"  <r:Expr> => SimplExpr::BinOp(Box::new(l), BinOp::LT, Box::new(r)),
+  <l:Expr> "=~" <r:Expr> => SimplExpr::BinOp(Box::new(l), BinOp::RegexMatch, Box::new(r)),
+
+  #[precedence(level="5")] #[assoc(side="left")]
+  <l:Expr> "&&"  <r:Expr> => SimplExpr::BinOp(Box::new(l), BinOp::And, Box::new(r)),
+  <l:Expr> "||"  <r:Expr> => SimplExpr::BinOp(Box::new(l), BinOp::Or, Box::new(r)),
+  <l:Expr> "?:"  <r:Expr> => SimplExpr::BinOp(Box::new(l), BinOp::Elvis, Box::new(r)),
+
+  #[precedence(level="6")] #[assoc(side="right")]
+  <cond:Expr> "?" <then:ExprReset> ":" <els:Expr> => SimplExpr::IfElse(Box::new(cond), Box::new(then), Box::new(els)),
+};
+
+ExprReset = <Expr>;
+
+Number: SimplExpr = r"[+-]?(?:[0-9]+[.])?[0-9]+" => SimplExpr::Literal(<>.to_string());
+Ident: String = r"[a-zA-Z_][^\s{}\(\)]*" => <>.to_string();
diff --git a/src/snapshots/simplexpr__tests__test-2.snap b/src/snapshots/simplexpr__tests__test-2.snap
new file mode 100644
index 0000000..9d2e4fb
--- /dev/null
+++ b/src/snapshots/simplexpr__tests__test-2.snap
@@ -0,0 +1,16 @@
+---
+source: src/lib.rs
+expression: "p.parse(\"2 + 5\")"
+
+---
+Ok(
+    BinOp(
+        Literal(
+            "2",
+        ),
+        Plus,
+        Literal(
+            "5",
+        ),
+    ),
+)
diff --git a/src/snapshots/simplexpr__tests__test-3.snap b/src/snapshots/simplexpr__tests__test-3.snap
new file mode 100644
index 0000000..ed8b2c9
--- /dev/null
+++ b/src/snapshots/simplexpr__tests__test-3.snap
@@ -0,0 +1,34 @@
+---
+source: src/lib.rs
+expression: "p.parse(\"2 * 5 + 1 * 1 + 3\")"
+
+---
+Ok(
+    BinOp(
+        BinOp(
+            BinOp(
+                Literal(
+                    "2",
+                ),
+                Times,
+                Literal(
+                    "5",
+                ),
+            ),
+            Plus,
+            BinOp(
+                Literal(
+                    "1",
+                ),
+                Times,
+                Literal(
+                    "1",
+                ),
+            ),
+        ),
+        Plus,
+        Literal(
+            "3",
+        ),
+    ),
+)
diff --git a/src/snapshots/simplexpr__tests__test-4.snap b/src/snapshots/simplexpr__tests__test-4.snap
new file mode 100644
index 0000000..1c5c5f5
--- /dev/null
+++ b/src/snapshots/simplexpr__tests__test-4.snap
@@ -0,0 +1,22 @@
+---
+source: src/lib.rs
+expression: "p.parse(\"(1 + 2) * 2\")"
+
+---
+Ok(
+    BinOp(
+        BinOp(
+            Literal(
+                "1",
+            ),
+            Plus,
+            Literal(
+                "2",
+            ),
+        ),
+        Times,
+        Literal(
+            "2",
+        ),
+    ),
+)
diff --git a/src/snapshots/simplexpr__tests__test-5.snap b/src/snapshots/simplexpr__tests__test-5.snap
new file mode 100644
index 0000000..f71ba69
--- /dev/null
+++ b/src/snapshots/simplexpr__tests__test-5.snap
@@ -0,0 +1,24 @@
+---
+source: src/lib.rs
+expression: "p.parse(\"1 + true ? 2 : 5\")"
+
+---
+Ok(
+    IfElse(
+        BinOp(
+            Literal(
+                "1",
+            ),
+            Plus,
+            Literal(
+                "true",
+            ),
+        ),
+        Literal(
+            "2",
+        ),
+        Literal(
+            "5",
+        ),
+    ),
+)
diff --git a/src/snapshots/simplexpr__tests__test-6.snap b/src/snapshots/simplexpr__tests__test-6.snap
new file mode 100644
index 0000000..4efff48
--- /dev/null
+++ b/src/snapshots/simplexpr__tests__test-6.snap
@@ -0,0 +1,30 @@
+---
+source: src/lib.rs
+expression: "p.parse(\"1 + true ? 2 : 5 + 2\")"
+
+---
+Ok(
+    IfElse(
+        BinOp(
+            Literal(
+                "1",
+            ),
+            Plus,
+            Literal(
+                "true",
+            ),
+        ),
+        Literal(
+            "2",
+        ),
+        BinOp(
+            Literal(
+                "5",
+            ),
+            Plus,
+            Literal(
+                "2",
+            ),
+        ),
+    ),
+)
diff --git a/src/snapshots/simplexpr__tests__test-7.snap b/src/snapshots/simplexpr__tests__test-7.snap
new file mode 100644
index 0000000..ff662bd
--- /dev/null
+++ b/src/snapshots/simplexpr__tests__test-7.snap
@@ -0,0 +1,30 @@
+---
+source: src/lib.rs
+expression: "p.parse(\"1 + (if true then 2 else 5) + 2\")"
+
+---
+Ok(
+    BinOp(
+        BinOp(
+            Literal(
+                "1",
+            ),
+            Plus,
+            IfElse(
+                Literal(
+                    "true",
+                ),
+                Literal(
+                    "2",
+                ),
+                Literal(
+                    "5",
+                ),
+            ),
+        ),
+        Plus,
+        Literal(
+            "2",
+        ),
+    ),
+)
diff --git a/src/snapshots/simplexpr__tests__test-8.snap b/src/snapshots/simplexpr__tests__test-8.snap
new file mode 100644
index 0000000..976aa45
--- /dev/null
+++ b/src/snapshots/simplexpr__tests__test-8.snap
@@ -0,0 +1,18 @@
+---
+source: src/lib.rs
+expression: "p.parse(\"foo(1, 2)\")"
+
+---
+Ok(
+    FunctionCall(
+        "foo",
+        [
+            Literal(
+                "1",
+            ),
+            Literal(
+                "2",
+            ),
+        ],
+    ),
+)
diff --git a/src/snapshots/simplexpr__tests__test.snap b/src/snapshots/simplexpr__tests__test.snap
new file mode 100644
index 0000000..929695f
--- /dev/null
+++ b/src/snapshots/simplexpr__tests__test.snap
@@ -0,0 +1,10 @@
+---
+source: src/lib.rs
+expression: "p.parse(\"1\")"
+
+---
+Ok(
+    Literal(
+        "1",
+    ),
+)