why not literals

programs/aidl/assets/core.idl

@@ -1,4 +1,5 @@
 Type Byte = U8;
+Type Int = U32;
 Type String = Vector<Byte>;
 
 Enumurate Boolean {

programs/aidl/assets/vfs.idl

@@ -1,7 +1,7 @@
 // core provides lots of useful types like String and Byte
 Use core;
 
-Constant VERSION Version {
+Constant VERSION = Version {
     major: 1,
     minor: 0,
     patch: 0,

programs/aidl/assets/why.idl

@@ -1,4 +1,5 @@
 Use core.Byte;
 Use core.Int;
 
-Alias Thing = Byte;
+Constant Hi = "WHY???/\n";
+Alias Yo = Byte;

programs/aidl/src/ast.rs

@@ -40,6 +40,7 @@ pub struct ItemAlias {
 #[derive(Debug)]
 pub struct ItemConstant {
     pub name: String,
+    pub expr: Expr
 }
 
 #[derive(Debug)]
@@ -56,6 +57,7 @@ pub enum Expr {
 pub enum Literal {
     String(String),
     Number(NumberLiteral),
+    Char(char)
 }
 
 #[derive(Debug)]

programs/aidl/src/lexer.rs

@@ -41,6 +41,19 @@ pub enum Token {
     #[token(".")]
     Dot,
 
+    // why
+    #[regex("\"(?s:[^\"\\\\]|\\\\.)*\"", |lex| dbg!(lex.slice()).strip_prefix('"')?.strip_suffix('"').map(ToOwned::to_owned))]
+    StringLiteral(String),
+
+    #[regex(r"'.'", |lex| lex.slice().strip_prefix('\'')?.strip_suffix('\'')?.parse().ok())]
+    CharLiteral(char),
+
+    #[regex(r#"(-)?\d+"#, |lex| lex.slice().parse().ok())]
+    NumberLiteral(i64),
+
+    #[regex(r"(ptr|u8|i8|u16|i16|u32|i32|u64|i64|f32|f64)", |lex| NumberSuffix::lexer(lex.slice()).next().and_then(Result::ok))]
+    NumberSuffix(NumberSuffix),
+
     #[regex(r#"[a-zA-Z_][a-zA-Z\d_]*"#, |lex| Ident::lexer(lex.slice()).next().and_then(Result::ok))]
     Ident(Ident),
 
@@ -62,10 +75,36 @@ pub enum Ident {
     Alias,
     #[token("Use")]
     Use,
-    #[regex(r"[A-z]+", |lex| lex.slice().parse().ok())]
+    #[regex(r"[a-zA-Z_][a-zA-Z\d_]*", |lex| lex.slice().parse().ok())]
     Other(String),
 }
 
+#[derive(Logos, Debug, PartialEq, Eq)]
+pub enum NumberSuffix {
+    #[token("Ptr")]
+    Ptr,
+    #[token("u8")]
+    U8,
+    #[token("i8")]
+    I8,
+    #[token("u16")]
+    U16,
+    #[token("i16")]
+    I16,
+    #[token("u32")]
+    U32,
+    #[token("i32")]
+    I32,
+    #[token("u64")]
+    U64,
+    #[token("i64")]
+    I64,
+    #[token("f32")]
+    F32,
+    #[token("f64")]
+    F64,
+}
+
 #[derive(Debug, Clone)]
 pub struct Span(pub Range<usize>);
 impl Span {

programs/aidl/src/main.rs

@@ -1,5 +1,8 @@
+#![feature(result_option_inspect)]
 #![allow(non_snake_case)]
 
+use lexer::Token;
+use logos::Logos;
 use parser::Parser;
 
 mod ast;

programs/aidl/src/parser/expr.rs

@@ -0,0 +1,51 @@
+use crate::{
+    ast::{Expr, Literal, NumberLiteral},
+    lexer::{NumberSuffix, Spanned, Token},
+    unwrap_match,
+};
+
+use super::{Parser, ParserError};
+
+impl<'a> Parser<'a> {
+    pub fn ask_expr(&mut self) -> Result<Spanned<Expr>, ParserError> {
+        let Spanned(token, _) = self.tokens.peek()?;
+        Ok(match token {
+            Token::StringLiteral(_) | Token::NumberLiteral(_) | Token::CharLiteral(_) => {
+                self._ask_literal()?.map(Expr::Literal)
+            }
+            _ => return Err(self.expected("an expression")),
+        })
+    }
+
+    fn _ask_literal(&mut self) -> Result<Spanned<Literal>, ParserError> {
+        let Spanned(token, mut span) = self.tokens.next()?;
+        Ok(match token {
+            Token::StringLiteral(string) => Spanned(Literal::String(string), span),
+            Token::CharLiteral(chr) => Spanned(Literal::Char(chr), span),
+            Token::NumberLiteral(number) => {
+                let lit = if let Spanned(Token::NumberSuffix(_), sp) = self.tokens.peek()? {
+                    span = span + sp;
+
+                    use NumberLiteral::*;
+                    Literal::Number(
+                        match unwrap_match!(
+                            self.tokens.next()?, Spanned(Token::NumberSuffix(suffering), _) => suffering) // eat suffix
+                        {
+                            NumberSuffix::Ptr => Ptr(number as usize),
+                            NumberSuffix::U8 => U8(number as u8),
+                            NumberSuffix::I8 => I8(number as i8),
+                            NumberSuffix::U16 => U16(number as u16),
+                            NumberSuffix::I16 => I16(number as i16),
+                            _ => todo!(),
+                        },
+                    )
+                } else {
+                    Literal::Number(NumberLiteral::Infer(number))
+                };
+
+                Spanned(lit, span)
+            }
+            _ => return Err(self.expected("a literal")),
+        })
+    }
+}

programs/aidl/src/parser/mod.rs

@@ -1,12 +1,14 @@
-use logos::{Lexer, Logos, SpannedIter};
+mod expr;
+mod interface;
+mod structure;
+
+use logos::{Lexer, Logos};
 
 use crate::{
     ast::{IDLModule, Item, ItemAlias, ItemConstant, ItemInterface, ModulePath, UseDecl},
     lexer::{Ident, Span, Spanned, Token},
 };
-use std::iter::{Filter, Iterator, Peekable};
+use std::iter::Iterator;
-
-type Wtf<'a> = Peekable<Filter<&'a mut Lexer<'a, Token>, Box<dyn Fn(&Result<Token, ()>) -> bool>>>;
 
 struct TokenIterator<'a> {
     lexer: Lexer<'a, Token>,
@@ -54,7 +56,7 @@ impl<'a> TokenIterator<'a> {
     }
 }
 
-pub struct Parser<'a> {
+pub(crate) struct Parser<'a> {
     tokens: TokenIterator<'a>,
 }
 
@@ -65,6 +67,10 @@ impl<'a> Parser<'a> {
         }
     }
 
+    fn eat(&mut self) {
+        let _ = self.tokens.next();
+    }
+
     fn get_real(
         &mut self,
         matcher: impl Fn(&Token) -> bool,
@@ -163,7 +169,15 @@ impl<'a> Parser<'a> {
     }
 
     fn ask_constant(&mut self) -> Result<Spanned<ItemConstant>, ParserError> {
-        Err(self.expected("the constant to be implemented"))
+        let Spanned(_, kSp) = self.get_real(
+            |token| matches!(token, Token::Ident(Ident::Constant)),
+            "`Constant`",
+        )?;
+        let Spanned(name, nSp) = self.ask_ident()?;
+        let Spanned(_, eqSp) = self.get_real(|token| matches!(token, Token::Equals), "`=`")?;
+        let Spanned(expr, exprSp) = self.ask_expr()?;
+
+        Ok(Spanned::new(ItemConstant { name, expr }, [kSp, nSp, eqSp, exprSp, self.semi()?]))
     }
 
     fn ask_item(&mut self) -> Result<Spanned<Item>, ParserError> {
@@ -228,6 +242,10 @@ fn fill_while<T>(
     Ok(real)
 }
 
+pub fn parse(source: &str) -> Result<IDLModule, ParserError> {
+    Parser::new(source).parse()
+}
+
 #[derive(thiserror::Error, Debug)]
 pub enum ParserError {
     // expected, got

programs/aidl/status.md

@@ -0,0 +1,8 @@
+# aidl status
+
+## parser
+[x] `Use module.thing`
+[x] `Alias Thing = OtherThing`
+
+## codegen
+TODO!