Merge pull request #435 from Alex-Fischman/static_parser

Static parser

src/ast/desugar.rs

@@ -3,17 +3,13 @@ use crate::*;
 
 pub struct Desugar {
     pub(crate) fresh_gen: SymbolGen,
-    // Store the parser because it takes some time
-    // on startup for some reason
-    parser: ast::parse::ProgramParser,
 }
 
 impl Default for Desugar {
     fn default() -> Self {
         Self {
             // the default reserved string in egglog is "_"
             fresh_gen: SymbolGen::new("_".repeat(2)),
-            parser: ast::parse::ProgramParser::new(),
         }
     }
 }
@@ -230,7 +226,7 @@ pub(crate) fn desugar_command(
             let s = std::fs::read_to_string(&file)
                 .unwrap_or_else(|_| panic!("{} Failed to read file {file}", span.get_quote()));
             return desugar_commands(
-                desugar.parse_program(Some(file), &s)?,
+                parse_program(Some(file), &s)?,
                 desugar,
                 get_all_proofs,
                 seminaive_transform,
@@ -387,7 +383,6 @@ impl Clone for Desugar {
     fn clone(&self) -> Self {
         Self {
             fresh_gen: self.fresh_gen.clone(),
-            parser: ast::parse::ProgramParser::new(),
         }
     }
 }
@@ -406,20 +401,4 @@ impl Desugar {
         let res = desugar_commands(program, self, get_all_proofs, seminaive_transform)?;
         Ok(res)
     }
-
-    pub fn parse_program(
-        &self,
-        filename: Option<String>,
-        input: &str,
-    ) -> Result<Vec<Command>, Error> {
-        let filename = filename.unwrap_or_else(|| DEFAULT_FILENAME.to_string());
-        let srcfile = Arc::new(SrcFile {
-            name: filename,
-            contents: Some(input.to_string()),
-        });
-        Ok(self
-            .parser
-            .parse(&srcfile, input)
-            .map_err(|e| e.map_token(|tok| tok.to_string()))?)
-    }
 }

src/ast/mod.rs

@@ -14,6 +14,24 @@ lalrpop_mod!(
     "/ast/parse.rs"
 );
 
+// For some reason the parser is slow to construct so
+// we make it static and only construct it once.
+lazy_static! {
+    static ref PARSER: parse::ProgramParser = Default::default();
+}
+
+/// Parse a file into a program.
+pub fn parse_program(filename: Option<String>, input: &str) -> Result<Vec<Command>, Error> {
+    let filename = filename.unwrap_or_else(|| DEFAULT_FILENAME.to_string());
+    let srcfile = Arc::new(SrcFile {
+        name: filename,
+        contents: Some(input.to_string()),
+    });
+    Ok(PARSER
+        .parse(&srcfile, input)
+        .map_err(|e| e.map_token(|tok| tok.to_string()))?)
+}
+
 use crate::{
     core::{GenericAtom, GenericAtomTerm, HeadOrEq, Query, ResolvedCall},
     *,

src/lib.rs

@@ -1458,14 +1458,6 @@ impl EGraph {
         Ok(self.flush_msgs())
     }
 
-    pub fn parse_program(
-        &self,
-        filename: Option<String>,
-        input: &str,
-    ) -> Result<Vec<Command>, Error> {
-        self.desugar.parse_program(filename, input)
-    }
-
     /// Takes a source program `input`, parses it, runs it, and returns a list of messages.
     ///
     /// `filename` is an optional argument to indicate the source of
@@ -1476,7 +1468,7 @@ impl EGraph {
         filename: Option<String>,
         input: &str,
     ) -> Result<Vec<String>, Error> {
-        let parsed = self.desugar.parse_program(filename, input)?;
+        let parsed = parse_program(filename, input)?;
         self.run_program(parsed)
     }