113 lines
3.4 KiB
Rust
Executable File
113 lines
3.4 KiB
Rust
Executable File
use crate::error_handling::{MistiError, SyntaxError};
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mod binding;
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mod expression;
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mod function_declaration;
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mod utils;
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pub mod ast;
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use crate::lexic::token::{Token, TokenType};
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use ast::ModuleAST;
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use self::ast::TopLevelDeclaration;
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#[derive(Debug)]
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pub enum SyntaxResult {
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///
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/// A construct has been found
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Ok(TopLevelDeclaration, usize),
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///
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/// No construct was found
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None,
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///
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/// A construct was found, but there was an error parsing it
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Err(SyntaxError),
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}
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/// Constructs the Misti AST from a vector of tokens
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pub fn construct_ast<'a>(tokens: &'a Vec<Token>) -> Result<ModuleAST, MistiError> {
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let mut top_level_declarations = Vec::new();
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let token_amount = tokens.len();
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let mut current_pos = 0;
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// Minus one because the last token is always EOF
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while current_pos < token_amount - 1 {
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// Ignore newlines
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if tokens[current_pos].token_type == TokenType::NewLine {
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current_pos += 1;
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continue;
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}
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match next_construct(tokens, current_pos) {
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SyntaxResult::Ok(module, next_pos) => {
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top_level_declarations.push(module);
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current_pos = next_pos;
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}
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SyntaxResult::None => {
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return Err(MistiError::Syntax(SyntaxError {
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reason: String::from("PARSER couldn't parse any construction"),
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// FIXME: This should get the position of the _token_ that current_pos points to
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error_start: current_pos,
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error_end: current_pos,
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}));
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}
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SyntaxResult::Err(err) => return Err(MistiError::Syntax(err)),
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}
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}
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Ok(ModuleAST {
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declarations: top_level_declarations,
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})
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}
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fn next_construct<'a>(tokens: &'a Vec<Token>, current_pos: usize) -> SyntaxResult {
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None.or_else(|| binding::try_parse(tokens, current_pos))
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.or_else(|| function_declaration::try_parse(tokens, current_pos))
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.unwrap_or_else(|| SyntaxResult::None)
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn should_parse_top_level_construct_with_trailing_newline() {
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let input = String::from("fun f1(){}\n");
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let tokens = crate::lexic::get_tokens(&input).unwrap();
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let declarations = construct_ast(&tokens).unwrap().declarations;
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assert_eq!(declarations.len(), 1);
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match declarations.get(0).unwrap() {
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TopLevelDeclaration::Binding(_) => panic!("Expected a function declaration"),
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TopLevelDeclaration::FunctionDeclaration(_f) => {
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assert!(true)
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}
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}
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}
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#[test]
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fn should_parse_2_top_level_construct() {
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let input = String::from("fun f1(){} fun f2() {}");
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let tokens = crate::lexic::get_tokens(&input).unwrap();
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let declarations = construct_ast(&tokens).unwrap().declarations;
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assert_eq!(declarations.len(), 2);
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match declarations.get(0).unwrap() {
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TopLevelDeclaration::Binding(_) => panic!("Expected a function declaration"),
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TopLevelDeclaration::FunctionDeclaration(_f) => {
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assert!(true)
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}
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}
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match declarations.get(1).unwrap() {
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TopLevelDeclaration::Binding(_) => panic!("Expected a function declaration"),
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TopLevelDeclaration::FunctionDeclaration(_f) => {
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assert!(true)
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}
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}
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}
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}
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