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Add variable declaration parsing

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Vili Sinervä 2025-01-31 17:58:29 +02:00
parent 97ae0e5ce6
commit 5d69d05c7b
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GPG key ID: DF8FEAF54EFAC996
1 changed files with 28 additions and 2 deletions
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30
src/compiler/parser/mod.rs
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@ -10,7 +10,7 @@ use crate::compiler::{
pub fn parse<'source>(tokens: &[Token<'source>]) -> Expression<'source> {
let mut pos = 0;
let result = parse_expression(0, &mut pos, tokens);
let result = parse_block_level_expressions(&mut pos, tokens);
if pos != tokens.len() {
panic!(
@ -22,6 +22,20 @@ pub fn parse<'source>(tokens: &[Token<'source>]) -> Expression<'source> {
result
}
// Horrible name, basically used to get the full expressions contained
// in blocks or at the top level of the program
fn parse_block_level_expressions<'source>(
pos: &mut usize,
tokens: &[Token<'source>],
) -> Expression<'source> {
// Special handling for variable declaration, since it is only allowed in very specifc places
if peek(pos, tokens).text == "var" {
parse_var_declaration(pos, tokens)
} else {
parse_expression(0, pos, tokens)
}
}
fn parse_expression<'source>(
level: usize,
pos: &mut usize,
@ -82,6 +96,7 @@ fn parse_term<'source>(pos: &mut usize, tokens: &[Token<'source>]) -> Expression
TokenType::Identifier => match token.text {
"if" => parse_conditional(pos, tokens),
"true" | "false" => parse_bool_literal(pos, tokens),
"var" => panic!("Invalid variable declaration {}", token),
_ => {
if peek(&mut (*pos + 1), tokens).text == "(" {
parse_function(pos, tokens)
@ -99,6 +114,17 @@ fn parse_term<'source>(pos: &mut usize, tokens: &[Token<'source>]) -> Expression
}
}
fn parse_var_declaration<'source>(
pos: &mut usize,
tokens: &[Token<'source>],
) -> Expression<'source> {
consume_string(pos, tokens, "var");
let name = consume_type(pos, tokens, TokenType::Identifier).text;
consume_string(pos, tokens, "=");
let value = parse_expression(0, pos, tokens);
VarDeclaration(name, Box::new(value))
}
fn parse_conditional<'source>(pos: &mut usize, tokens: &[Token<'source>]) -> Expression<'source> {
consume_string(pos, tokens, "if");
let condition = Box::new(parse_expression(0, pos, tokens));
@ -128,7 +154,7 @@ fn parse_block<'source>(pos: &mut usize, tokens: &[Token<'source>]) -> Expressio
let mut expressions = Vec::new();
loop {
expressions.push(parse_expression(0, pos, tokens));
expressions.push(parse_block_level_expressions(pos, tokens));
if peek(pos, tokens).text == "}" {
break;