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Expression parsing work

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This commit is contained in:
greg 2016-01-13 23:29:18 -08:00
parent fff9cb7d25
commit 31da25a66e
1 changed files with 12 additions and 4 deletions
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16
src/parser.rs
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@ -192,10 +192,19 @@ impl Parser {
fn expression(&mut self) -> ParseResult<Expression> { fn expression(&mut self) -> ParseResult<Expression> {
use tokenizer::Token::*; use tokenizer::Token::*;
let expr: Expression = match self.next() { let mut lhr: Expression = try!(self.primary_expression());
Some(Identifier(s)) => Expression::StringLiteral(s), Ok(lhr)
_ => panic!("bad expression parse"), }
fn primary_expression(&mut self) -> ParseResult<Expression> {
use tokenizer::Token::*;
let expr = match self.peek() {
Some(NumLiteral(n)) => { self.next(); Expression::Number(n) },
Some(StrLiteral(s)) => { self.next(); Expression::StringLiteral(s) },
Some(Identifier(var)) => { self.next(); Expression::Variable(var) },
_ => unimplemented!()
}; };
Ok(expr) Ok(expr)
} }
} }
@ -204,4 +213,3 @@ pub fn parse(tokens: &[Token], _parsed_tree: &[ASTNode]) -> ParseResult<AST> {
let mut parser = Parser::initialize(tokens); let mut parser = Parser::initialize(tokens);
parser.program() parser.program()
} }