Switch Parsing Algorithm From Pest(PEG) to LALRPOP(LALR(1))

.vscode/settings.json

@@ -1,29 +1,31 @@
 {
   "cSpell.words": [
     "clippy",
+    "codepoints",
     "Commentable",
     "dedup",
     "downcasted",
     "downcasting",
+    "elif",
     "encodable",
     "grcov",
+    "lalrpop",
     "nonstreamed",
-    "prec",
+    "peekable",
     "rsplit",
     "RUSTDOCFLAGS",
     "rustup",
     "slicec",
     "struct",
     "subtoken",
     "subtokens",
+    "tokenizes",
     "typealias",
     "typeref",
     "uncasted",
-    "unpatchable",
     "unprefixed",
     "Unsize",
     "upcasting",
-    "userdata",
     "varint",
     "varuint"
   ],

Cargo.toml

@@ -14,13 +14,18 @@ edition = "2021"
 clap = { version = "4.0.5", features = ["derive"] }
 console = "0.15.1"
 convert_case = "0.5.0"
+lalrpop-util = "0.19.8"
 pest = "=2.3.0"
 pest_consume = "=1.1.3"
 pest_derive = "=2.3.0"
 # derive feature allows structs to derive Serialize automatically
 serde = { version="1.0.144", features = ["derive"] }
 serde_json = "1.0.85"
 
+[build-dependencies]
+# The default features enable a built-in lexer. We supply our own lexer so we don't need these.
+lalrpop = { version = "0.19.8", default-features = false }
+
 [dev-dependencies]
 test-case = "2.0.2"
 

build.rs

@@ -0,0 +1,8 @@
+// Copyright (c) ZeroC, Inc. All rights reserved.
+
+extern crate lalrpop;
+
+fn main() {
+    // Recursively finds any files ending with `.lalrpop` in the `src` directory and generates parsers from them.
+    lalrpop::process_root().unwrap();
+}

src/ast/mod.rs

@@ -22,7 +22,6 @@ use std::convert::{TryFrom, TryInto};
 ///
 /// This function fails fast, so if any phase of patching fails, we skip any remaining phases.
 pub(crate) unsafe fn patch_ast(mut parsed_data: ParsedData) -> ParserResult {
-    patchers::parent_patcher::patch_ast(&mut parsed_data.ast); // TODO remove this when we switch to LALRpop
     parsed_data = patchers::type_ref_patcher::patch_ast(parsed_data)?;
     parsed_data = patchers::encoding_patcher::patch_ast(parsed_data)?;
 

src/ast/patchers/mod.rs

@@ -3,5 +3,4 @@
 //! TODO write a doc comment for the module.
 
 pub mod encoding_patcher;
-pub mod parent_patcher; // TODO remove this when we switch to LALRpop.
 pub mod type_ref_patcher;