File size: 4,675 Bytes
59da845 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 | use nom::{
branch::alt,
bytes::complete::{tag, take_while1, take_until, take_while},
character::complete::{alpha1, alphanumeric1, char, digit1, multispace0, multispace1, anychar},
combinator::{map, map_res, recognize, value, eof, opt},
multi::many0,
sequence::{delimited, pair, preceded, tuple},
IResult,
};
use crate::compiler::lexer::Token;
use std::str::FromStr;
pub struct Lexer;
impl Lexer {
pub fn tokenize(input: &str) -> IResult<&str, Vec<Token>> {
many0(preceded(
// Skip whitespace and comments
alt((
multispace1,
// Line comment //
recognize(pair(tag("//"), take_while(|c| c != '\n' && c != '\r'))),
// Block comment /* */
recognize(delimited(tag("/*"), take_until("*/"), tag("*/"))),
)),
// Parse tokens
alt((
// Keywords & Types
Self::parse_keyword,
// Literals
Self::parse_double_literal,
Self::parse_int_literal,
Self::parse_string_literal,
Self::parse_bool_literal,
// Identifiers
Self::parse_identifier,
// Operators & Punctuation (Order matters for prefix matching, e.g. == before =)
Self::parse_operator,
Self::parse_punctuation,
))
))(input)
}
fn parse_keyword(input: &str) -> IResult<&str, Token> {
alt((
value(Token::Int, tag("int")),
value(Token::Double, tag("double")),
value(Token::String, tag("string")),
value(Token::Bool, tag("bool")),
value(Token::Void, tag("void")),
value(Token::Input, tag("input")),
value(Token::If, tag("if")),
value(Token::Else, tag("else")),
value(Token::For, tag("for")),
value(Token::While, tag("while")),
value(Token::Return, tag("return")),
value(Token::MqlTick, tag("MqlTick")),
value(Token::MqlRates, tag("MqlRates")),
))(input)
}
fn parse_bool_literal(input: &str) -> IResult<&str, Token> {
alt((
value(Token::BoolLiteral(true), tag("true")),
value(Token::BoolLiteral(false), tag("false")),
))(input)
}
fn parse_identifier(input: &str) -> IResult<&str, Token> {
map(
recognize(pair(
alt((alpha1, tag("_"))),
take_while(|c: char| c.is_alphanumeric() || c == '_')
)),
|s: &str| Token::Identifier(s.to_string())
)(input)
}
fn parse_int_literal(input: &str) -> IResult<&str, Token> {
map_res(digit1, |s: &str| s.parse::<i64>().map(Token::IntLiteral))(input)
}
fn parse_double_literal(input: &str) -> IResult<&str, Token> {
map_res(
recognize(tuple((
digit1,
char('.'),
digit1
))),
|s: &str| s.parse::<f64>().map(Token::DoubleLiteral)
)(input)
}
fn parse_string_literal(input: &str) -> IResult<&str, Token> {
map(
delimited(char('"'), take_while(|c| c != '"'), char('"')),
|s: &str| Token::StringLiteral(s.to_string())
)(input)
}
fn parse_operator(input: &str) -> IResult<&str, Token> {
alt((
value(Token::Equals, tag("==")),
value(Token::NotEquals, tag("!=")),
value(Token::GreaterEq, tag(">=")),
value(Token::LessEq, tag("<=")),
value(Token::And, tag("&&")),
value(Token::Or, tag("||")),
value(Token::Assign, tag("=")),
value(Token::Greater, tag(">")),
value(Token::Less, tag("<")),
value(Token::Plus, tag("+")),
value(Token::Minus, tag("-")),
value(Token::Star, tag("*")),
value(Token::Slash, tag("/")),
value(Token::Not, tag("!")),
))(input)
}
fn parse_punctuation(input: &str) -> IResult<&str, Token> {
alt((
value(Token::OpenParen, tag("(")),
value(Token::CloseParen, tag(")")),
value(Token::OpenBrace, tag("{")),
value(Token::CloseBrace, tag("}")),
value(Token::OpenBracket, tag("[")),
value(Token::CloseBracket, tag("]")),
value(Token::Comma, tag(",")),
value(Token::Semicolon, tag(";")),
value(Token::Dot, tag(".")),
))(input)
}
}
|