Some basic parsing, with interned strings.

src/syntax.rs

@@ -1,5 +1,40 @@
-//use lalrpop_util::lalrpop_mod;
+use lalrpop_util::lalrpop_mod;
 
-pub mod tokens;
-//lalrpop_mod!(pub parser);
-pub mod ast;
+mod tokens;
+mod token_stream;
+lalrpop_mod!(parser, "/syntax/parser.rs");
+mod ast;
+
+pub use crate::syntax::ast::*;
+use crate::syntax::parser::ProgramParser;
+use crate::syntax::tokens::Token;
+use crate::syntax::token_stream::{LexerError, Location, TokenStream};
+use lalrpop_util::ParseError;
+use std::fs;
+use std::io;
+
+pub enum ParserError {
+    IOError(io::Error),
+    ParseError(ParseError<Location,Token,LexerError>),
+}
+
+impl From<io::Error> for ParserError {
+    fn from(x: io::Error) -> Self {
+        ParserError::IOError(x)
+    }
+}
+
+impl From<ParseError<Location,Token,LexerError>> for ParserError {
+    fn from(x: ParseError<Location, Token, LexerError>) -> Self {
+        ParserError::ParseError(x)
+    }
+}
+
+impl Program {
+    pub fn from_file(filename: &str) -> Result<Program, ParserError> {
+        let metadata = fs::metadata(filename)?;
+        let mut buffer = String::with_capacity(metadata.len() as usize);
+        let lexer = TokenStream::from_file(filename, &mut buffer)?;
+        Ok(ProgramParser::new().parse(lexer)?)
+    }
+}