implement some initial f32 support

src/ast.rs

@@ -87,6 +87,7 @@ pub struct LocalVariable<'a> {
     pub name: &'a str,
     pub type_: Option<Type>,
     pub value: Option<Expression<'a>>,
+    pub defer: bool
 }
 
 #[derive(Debug)]
@@ -104,6 +105,7 @@ impl<'a> From<Expr<'a>> for Expression<'a> {
 #[derive(Debug)]
 pub enum Expr<'a> {
     I32Const(i32),
+    F32Const(f32),
     Variable {
         position: Position,
         name: &'a str,
@@ -129,6 +131,11 @@ pub enum Expr<'a> {
         name: &'a str,
         value: Box<Expression<'a>>,
     },
+    Cast {
+        position: Position,
+        value: Box<Expression<'a>>,
+        type_: Type,
+    },
 }
 
 #[derive(Debug, Clone, Copy)]

src/constfold.rs

@@ -78,14 +78,31 @@ fn fold_expr(expr: &mut ast::Expression) {
                     };
                     expr.expr = ast::Expr::I32Const(result);
                 }
+                (&ast::Expr::F32Const(left), &ast::Expr::F32Const(right)) => {
+                    use ast::Expr::*;
+                    expr.expr = match op {
+                        Add => F32Const(left + right),
+                        Sub => F32Const(left - right),
+                        Mul => F32Const(left * right),
+                        Div => F32Const(left / right),
+                        Rem | And | Or | Xor => return,
+                        Eq => I32Const((left == right) as i32),
+                        Ne => I32Const((left != right) as i32),
+                        Lt => I32Const((left < right) as i32),
+                        Le => I32Const((left <= right) as i32),
+                        Gt => I32Const((left > right) as i32),
+                        Ge => I32Const((left >= right) as i32),
+                    };
+                }
                 _ => (),
             }
         }
-        ast::Expr::I32Const(_) | ast::Expr::Variable { .. } => (),
+        ast::Expr::I32Const(_) | ast::Expr::F32Const(_) | ast::Expr::Variable { .. } => (),
         ast::Expr::LocalTee { ref mut value, .. } => fold_expr(value),
         ast::Expr::Loop { ref mut block, .. } => fold_block(block),
         ast::Expr::BranchIf {
             ref mut condition, ..
         } => fold_expr(condition),
+        ast::Expr::Cast { ref mut value, .. } => fold_expr(value),
     }
 }

src/emit.rs

@@ -111,6 +111,7 @@ struct FunctionContext<'a> {
     globals: &'a HashMap<&'a str, u32>,
     locals: &'a HashMap<&'a str, u32>,
     labels: Vec<String>,
+    deferred_inits: HashMap<&'a str, &'a ast::Expression<'a>>,
 }
 
 fn emit_function(func: &ast::Function, globals: &HashMap<&str, u32>) -> Function {
@@ -131,6 +132,7 @@ fn emit_function(func: &ast::Function, globals: &HashMap<&str, u32>) -> Function
         globals,
         locals: &locals,
         labels: vec![],
+        deferred_inits: HashMap::new(),
     };
 
     emit_block(&mut context, &func.body);
@@ -169,7 +171,7 @@ fn collect_locals<'a>(block: &ast::Block<'a>, locals: &mut Vec<(&'a str, ast::Ty
 
 fn collect_locals_expr<'a>(expr: &ast::Expression<'a>, locals: &mut Vec<(&'a str, ast::Type)>) {
     match &expr.expr {
-        ast::Expr::Variable { .. } | ast::Expr::I32Const(_) => (),
+        ast::Expr::Variable { .. } | ast::Expr::I32Const(_) | ast::Expr::F32Const(_) => (),
         ast::Expr::BinOp { left, right, .. } => {
             collect_locals_expr(left, locals);
             collect_locals_expr(right, locals);
@@ -177,10 +179,11 @@ fn collect_locals_expr<'a>(expr: &ast::Expression<'a>, locals: &mut Vec<(&'a str
         ast::Expr::BranchIf { condition, .. } => collect_locals_expr(condition, locals),
         ast::Expr::LocalTee { value, .. } => collect_locals_expr(value, locals),
         ast::Expr::Loop { block, .. } => collect_locals(block, locals),
+        ast::Expr::Cast { value, .. } => collect_locals_expr(value, locals),
     }
 }
 
-fn emit_block(ctx: &mut FunctionContext, block: &ast::Block) {
+fn emit_block<'a>(ctx: &mut FunctionContext<'a>, block: &'a ast::Block) {
     for stmt in &block.statements {
         match stmt {
             ast::Statement::Expression(e) => {
@@ -191,9 +194,13 @@ fn emit_block(ctx: &mut FunctionContext, block: &ast::Block) {
             }
             ast::Statement::LocalVariable(v) => {
                 if let Some(ref val) = v.value {
-                    emit_expression(ctx, val);
+                    if v.defer {
-                    ctx.function
+                        ctx.deferred_inits.insert(v.name, val);
-                        .instruction(&Instruction::LocalSet(*ctx.locals.get(v.name).unwrap()));
+                    } else {
+                        emit_expression(ctx, val);
+                        ctx.function
+                            .instruction(&Instruction::LocalSet(*ctx.locals.get(v.name).unwrap()));
+                    }
                 }
             }
             ast::Statement::Poke {
@@ -228,7 +235,7 @@ fn emit_block(ctx: &mut FunctionContext, block: &ast::Block) {
     }
 }
 
-fn emit_expression(ctx: &mut FunctionContext, expr: &ast::Expression) {
+fn emit_expression<'a>(ctx: &mut FunctionContext<'a>, expr: &'a ast::Expression) {
     match &expr.expr {
         ast::Expr::BinOp {
             left, op, right, ..
@@ -253,8 +260,19 @@ fn emit_expression(ctx: &mut FunctionContext, expr: &ast::Expression) {
                 (I32, Gt) => Instruction::I32GtS,
                 (I32, Ge) => Instruction::I32GeS,
 
+                (F32, Add) => Instruction::F32Add,
+                (F32, Sub) => Instruction::F32Sub,
+                (F32, Mul) => Instruction::F32Mul,
+                (F32, Div) => Instruction::F32Div,
+                (F32, Rem | And | Or | Xor) => unreachable!(),
+                (F32, Eq) => Instruction::F32Eq,
+                (F32, Ne) => Instruction::F32Neq,
+                (F32, Lt) => Instruction::F32Lt,
+                (F32, Le) => Instruction::F32Le,
+                (F32, Gt) => Instruction::F32Gt,
+                (F32, Ge) => Instruction::F32Ge,
+
                 (I64, _) => todo!(),
-                (F32, _) => todo!(),
                 (F64, _) => todo!(),
             });
         }
@@ -275,6 +293,9 @@ fn emit_expression(ctx: &mut FunctionContext, expr: &ast::Expression) {
         ast::Expr::I32Const(v) => {
             ctx.function.instruction(&Instruction::I32Const(*v));
         }
+        ast::Expr::F32Const(v) => {
+            ctx.function.instruction(&Instruction::F32Const(*v));
+        }
         ast::Expr::LocalTee { name, value, .. } => {
             emit_expression(ctx, value);
             let index = ctx.locals.get(*name).unwrap();
@@ -290,13 +311,31 @@ fn emit_expression(ctx: &mut FunctionContext, expr: &ast::Expression) {
         }
         ast::Expr::Variable { name, .. } => {
             if let Some(index) = ctx.locals.get(*name) {
-                ctx.function.instruction(&Instruction::LocalGet(*index));
+                if let Some(expr) = ctx.deferred_inits.remove(*name) {
+                    emit_expression(ctx, expr);
+                    ctx.function.instruction(&Instruction::LocalTee(*index));
+                } else {
+                    ctx.function.instruction(&Instruction::LocalGet(*index));
+                }
             } else if let Some(index) = ctx.globals.get(*name) {
                 ctx.function.instruction(&Instruction::GlobalGet(*index));
             } else {
                 unreachable!()
             }
         }
+        ast::Expr::Cast { value, type_, .. } => {
+            emit_expression(ctx, value);
+            use ast::Type::*;
+            let inst = match (value.type_.unwrap(), *type_) {
+                (t1, t2) if t1 == t2 => None,
+                (I32, F32) => Some(Instruction::F32ConvertI32S),
+                (F32, I32) => Some(Instruction::I32TruncF32S),
+                _ => todo!(),
+            };
+            if let Some(inst) = inst {
+                ctx.function.instruction(&inst);
+            }
+        }
     }
 }
 

src/parser.rs

@@ -6,7 +6,7 @@ use nom::{
     combinator::{self, cut, map, map_res, not, opt, peek, recognize, value},
     error::VerboseError,
     multi::{fold_many0, many0, many1, separated_list0},
-    sequence::{delimited, pair, preceded, separated_pair, terminated},
+    sequence::{delimited, pair, preceded, separated_pair, terminated, tuple},
     Finish,
 };
 
@@ -182,21 +182,25 @@ fn statement(s: &str) -> IResult<ast::Statement> {
 
 fn local_var(s: &str) -> IResult<ast::LocalVariable> {
     let (s, _) = ws(tag("let"))(s)?;
-    let (s, position) = ws(position)(s)?;
+    cut(move |s| {
-    let (s, name) = identifier(s)?;
+        let (s, defer) = opt(ws(tag("defer")))(s)?;
-    let (s, type_) = opt(preceded(ws(char(':')), type_))(s)?;
+        let (s, position) = ws(position)(s)?;
-    let (s, value) = opt(preceded(ws(char('=')), expression))(s)?;
+        let (s, name) = identifier(s)?;
-    let (s, _) = ws(char(';'))(s)?;
+        let (s, type_) = opt(preceded(ws(char(':')), type_))(s)?;
+        let (s, value) = opt(preceded(ws(char('=')), expression))(s)?;
+        let (s, _) = ws(char(';'))(s)?;
 
-    Ok((
+        Ok((
-        s,
+            s,
-        ast::LocalVariable {
+            ast::LocalVariable {
-            position,
+                position,
-            name: name,
+                name: name,
-            type_,
+                type_,
-            value: value.map(|v| v.into()),
+                value: value.map(|v| v.into()),
-        },
+                defer: defer.is_some()
-    ))
+            },
+        ))
+    })(s)
 }
 
 fn mem_location(s: &str) -> IResult<ast::MemoryLocation> {
@@ -236,7 +240,8 @@ fn expression_atom(s: &str) -> IResult<ast::Expr> {
                 value: Box::new(value.into()),
             },
         ),
-        map(integer, |v| ast::Expr::I32Const(v)),
+        map(float, ast::Expr::F32Const),
+        map(integer, ast::Expr::I32Const),
         map(ws(pair(position, identifier)), |(position, name)| {
             ast::Expr::Variable {
                 position,
@@ -266,12 +271,25 @@ fn branch_if(s: &str) -> IResult<ast::Expr> {
     })(s)
 }
 
-fn expression_product(s: &str) -> IResult<ast::Expr> {
+fn expression_cast(s: &str) -> IResult<ast::Expr> {
     let (s, mut init) = map(expression_atom, Some)(s)?;
+    fold_many0(
+        pair(ws(terminated(position, tag("as"))), type_),
+        move || init.take().unwrap(),
+        |value, (position, type_)| ast::Expr::Cast {
+            position,
+            value: Box::new(value.into()),
+            type_,
+        },
+    )(s)
+}
+
+fn expression_product(s: &str) -> IResult<ast::Expr> {
+    let (s, mut init) = map(expression_cast, Some)(s)?;
     fold_many0(
         pair(
             ws(pair(position, alt((char('*'), char('/'), char('%'))))),
-            expression_atom,
+            expression_cast,
         ),
         move || init.take().unwrap(),
         |left, ((position, op), right)| {
@@ -407,6 +425,13 @@ fn integer(s: &str) -> IResult<i32> {
     ))(s)
 }
 
+fn float(s: &str) -> IResult<f32> {
+    ws(map_res(
+        recognize(tuple((opt(char('-')), digit1, char('.'), digit1))),
+        |n: &str| n.parse::<f32>(),
+    ))(s)
+}
+
 fn type_(s: &str) -> IResult<ast::Type> {
     ws(alt((
         value(ast::Type::I32, tag("i32")),

src/typecheck.rs

@@ -126,6 +126,7 @@ fn tc_block<'a>(context: &mut Context<'a>, block: &mut ast::Block<'a>) -> Result
 fn tc_expression<'a>(context: &mut Context<'a>, expr: &mut ast::Expression<'a>) -> Result<()> {
     expr.type_ = match expr.expr {
         ast::Expr::I32Const(_) => Some(ast::Type::I32),
+        ast::Expr::F32Const(_) => Some(ast::Type::F32),
         ast::Expr::BinOp {
             position,
             op,
@@ -213,6 +214,20 @@ fn tc_expression<'a>(context: &mut Context<'a>, expr: &mut ast::Expression<'a>)
             }
             None
         }
+        ast::Expr::Cast {
+            position,
+            ref mut value,
+            type_,
+        } => {
+            tc_expression(context, value)?;
+            if value.type_.is_none() {
+                return Err(Error {
+                    position,
+                    message: "Cannot cast void".into(),
+                });
+            }
+            Some(type_)
+        }
     };
     Ok(())
 }

warptunnel.hw

@@ -0,0 +1,16 @@
+import "uw8.ram" memory(2);
+import "uw8.time" global mut time: i32;
+
+export fn tic() {
+    let i: i32;
+    loop pixels {
+        let defer x = (i % 320) as f32 - 160.1;
+        let defer y = (i / 320 - 128) as f32;
+        let defer dist = 10000.0 / (x*x + y*y);
+        let defer t = time as f32 / 20 as f32;
+
+        i?120 = (x * dist + t) as i32 ^ (y * dist + t) as i32;
+
+        branch_if (i := i + 1) < 320*256: pixels
+    }
+}