got trainride working

src/ast.rs

@@ -136,6 +136,17 @@ pub enum Expr<'a> {
         value: Box<Expression<'a>>,
         type_: Type,
     },
+    FuncCall {
+        position: Position,
+        name: &'a str,
+        params: Vec<Expression<'a>>
+    },
+    Select {
+        position: Position,
+        condition: Box<Expression<'a>>,
+        if_true: Box<Expression<'a>>,
+        if_false: Box<Expression<'a>>
+    }
 }
 
 #[derive(Debug, Clone, Copy)]

src/constfold.rs

@@ -104,5 +104,25 @@ fn fold_expr(expr: &mut ast::Expression) {
             ref mut condition, ..
         } => fold_expr(condition),
         ast::Expr::Cast { ref mut value, .. } => fold_expr(value),
+        ast::Expr::FuncCall {
+            name,
+            ref mut params,
+            ..
+        } => {
+            for param in params.iter_mut() {
+                fold_expr(param);
+            }
+            use ast::Expr::*;
+            let params: Vec<_> = params.iter().map(|e| &e.expr).collect();
+            expr.expr = match (name, params.as_slice()) {
+                ("sqrt", [F32Const(v)]) if *v >= 0.0 => F32Const(v.sqrt()),
+                _ => return,
+            };
+        }
+        ast::Expr::Select { ref mut condition, ref mut if_true, ref mut if_false, .. } => {
+            fold_expr(condition);
+            fold_expr(if_true);
+            fold_expr(if_false);
+        }
     }
 }

src/emit.rs

@@ -180,6 +180,21 @@ fn collect_locals_expr<'a>(expr: &ast::Expression<'a>, locals: &mut Vec<(&'a str
         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),
+        ast::Expr::FuncCall { params, .. } => {
+            for param in params {
+                collect_locals_expr(param, locals);
+            }
+        }
+        ast::Expr::Select {
+            condition,
+            if_true,
+            if_false,
+            ..
+        } => {
+            collect_locals_expr(condition, locals);
+            collect_locals_expr(if_true, locals);
+            collect_locals_expr(if_false, locals);
+        }
     }
 }
 
@@ -336,6 +351,26 @@ fn emit_expression<'a>(ctx: &mut FunctionContext<'a>, expr: &'a ast::Expression)
                 ctx.function.instruction(&inst);
             }
         }
+        ast::Expr::FuncCall { name, params, .. } => {
+            let mut types = vec![];
+            for param in params {
+                types.push(param.type_.unwrap());
+                emit_expression(ctx, param);
+            }
+            ctx.function
+                .instruction(&builtin_function(name, &types).unwrap());
+        }
+        ast::Expr::Select {
+            condition,
+            if_true,
+            if_false,
+            ..
+        } => {
+            emit_expression(ctx, if_true);
+            emit_expression(ctx, if_false);
+            emit_expression(ctx, condition);
+            ctx.function.instruction(&Instruction::Select);
+        }
     }
 }
 
@@ -355,3 +390,13 @@ fn map_block_type(t: Option<ast::Type>) -> BlockType {
         BlockType::Empty
     }
 }
+
+fn builtin_function(name: &str, params: &[ast::Type]) -> Option<Instruction<'static>> {
+    use ast::Type::*;
+    let inst = match (name, params) {
+        ("sqrt", &[F32]) => Instruction::F32Sqrt,
+        ("abs", &[F32]) => Instruction::F32Abs,
+        _ => return None,
+    };
+    Some(inst)
+}

src/main.rs

@@ -28,7 +28,14 @@ fn main() -> Result<()> {
     };
 
     constfold::fold_script(&mut script);
-    typecheck::tc_script(&mut script).unwrap();
+    if let Err(err) = typecheck::tc_script(&mut script) {
+        let line = input[..(input.len() - err.position.0)]
+            .chars()
+            .filter(|c| *c == '\n')
+            .count()
+            + 1;
+        bail!("{} in line {}", err.message, line);
+    }
     let wasm = emit::emit(&script);
 
     wasmparser::validate(&wasm)?;

src/parser.rs

@@ -167,7 +167,7 @@ fn statement(s: &str) -> IResult<ast::Statement> {
             terminated(
                 pair(
                     mem_location,
-                    ws(pair(position, preceded(char('='), expression))),
+                    cut(ws(pair(position, preceded(char('='), expression)))),
                 ),
                 ws(char(';')),
             ),
@@ -197,7 +197,7 @@ fn local_var(s: &str) -> IResult<ast::LocalVariable> {
                 name: name,
                 type_,
                 value: value.map(|v| v.into()),
-                defer: defer.is_some()
+                defer: defer.is_some(),
             },
         ))
     })(s)
@@ -225,7 +225,7 @@ fn mem_location(s: &str) -> IResult<ast::MemoryLocation> {
 }
 
 fn expression(s: &str) -> IResult<ast::Expr> {
-    expression_cmp(s)
+    expression_bit(s)
 }
 
 fn expression_atom(s: &str) -> IResult<ast::Expr> {
@@ -242,6 +242,36 @@ fn expression_atom(s: &str) -> IResult<ast::Expr> {
         ),
         map(float, ast::Expr::F32Const),
         map(integer, ast::Expr::I32Const),
+        map(
+            tuple((
+                terminated(ws(position), tag("select")),
+                preceded(ws(char('(')), expression),
+                preceded(ws(char(',')), expression),
+                delimited(ws(char(',')), expression, ws(char(')'))),
+            )),
+            |(position, condition, if_true, if_false)| ast::Expr::Select {
+                position,
+                condition: Box::new(condition.into()),
+                if_true: Box::new(if_true.into()),
+                if_false: Box::new(if_false.into()),
+            },
+        ),
+        map(
+            tuple((
+                ws(position),
+                identifier,
+                delimited(
+                    ws(char('(')),
+                    separated_list0(ws(char(',')), expression),
+                    ws(char(')')),
+                ),
+            )),
+            |(position, name, params)| ast::Expr::FuncCall {
+                position,
+                name,
+                params: params.into_iter().map(|p| p.into()).collect(),
+            },
+        ),
         map(ws(pair(position, identifier)), |(position, name)| {
             ast::Expr::Variable {
                 position,
@@ -333,33 +363,8 @@ fn expression_sum(s: &str) -> IResult<ast::Expr> {
     )(s)
 }
 
-fn expression_bit(s: &str) -> IResult<ast::Expr> {
-    let (s, mut init) = map(expression_sum, Some)(s)?;
-    fold_many0(
-        pair(
-            ws(pair(position, alt((char('&'), char('|'), char('^'))))),
-            expression_sum,
-        ),
-        move || init.take().unwrap(),
-        |left, ((position, op), right)| {
-            let op = match op {
-                '&' => ast::BinOp::And,
-                '|' => ast::BinOp::Or,
-                '^' => ast::BinOp::Xor,
-                _ => unreachable!(),
-            };
-            ast::Expr::BinOp {
-                position,
-                op,
-                left: Box::new(left.into()),
-                right: Box::new(right.into()),
-            }
-        },
-    )(s)
-}
-
 fn expression_cmp(s: &str) -> IResult<ast::Expr> {
-    let (s, mut init) = map(expression_bit, Some)(s)?;
+    let (s, mut init) = map(expression_sum, Some)(s)?;
     fold_many0(
         pair(
             ws(pair(
@@ -373,7 +378,7 @@ fn expression_cmp(s: &str) -> IResult<ast::Expr> {
                     tag(">"),
                 )),
             )),
-            expression_bit,
+            expression_sum,
         ),
         move || init.take().unwrap(),
         |left, ((position, op), right)| {
@@ -396,6 +401,31 @@ fn expression_cmp(s: &str) -> IResult<ast::Expr> {
     )(s)
 }
 
+fn expression_bit(s: &str) -> IResult<ast::Expr> {
+    let (s, mut init) = map(expression_cmp, Some)(s)?;
+    fold_many0(
+        pair(
+            ws(pair(position, alt((char('&'), char('|'), char('^'))))),
+            expression_cmp,
+        ),
+        move || init.take().unwrap(),
+        |left, ((position, op), right)| {
+            let op = match op {
+                '&' => ast::BinOp::And,
+                '|' => ast::BinOp::Or,
+                '^' => ast::BinOp::Xor,
+                _ => unreachable!(),
+            };
+            ast::Expr::BinOp {
+                position,
+                op,
+                left: Box::new(left.into()),
+                right: Box::new(right.into()),
+            }
+        },
+    )(s)
+}
+
 fn block_expression(s: &str) -> IResult<ast::Expr> {
     loop_(s)
 }

src/typecheck.rs

@@ -167,7 +167,7 @@ fn tc_expression<'a>(context: &mut Context<'a>, expr: &mut ast::Expression<'a>)
             } else {
                 return Err(Error {
                     position,
-                    message: "Variable not found".into(),
+                    message: format!("Variable '{}' not found", name),
                 });
             }
         }
@@ -228,6 +228,73 @@ fn tc_expression<'a>(context: &mut Context<'a>, expr: &mut ast::Expression<'a>)
             }
             Some(type_)
         }
+        ast::Expr::FuncCall {
+            position,
+            name,
+            ref mut params,
+        } => {
+            if let Some((ptypes, rtype)) = builtin_function_types(name) {
+                if params.len() != ptypes.len() {
+                    return Err(Error {
+                        position,
+                        message: format!(
+                            "Expected {} parameters but found {}",
+                            ptypes.len(),
+                            params.len()
+                        ),
+                    });
+                }
+                for (index, (ptype, param)) in ptypes.iter().zip(params.iter_mut()).enumerate() {
+                    tc_expression(context, param)?;
+                    if param.type_.is_none() || param.type_.unwrap() != *ptype {
+                        return Err(Error {
+                            position,
+                            message: format!(
+                                "Param {} is {:?} but should be {:?}",
+                                index + 1,
+                                param.type_,
+                                ptype
+                            ),
+                        });
+                    }
+                }
+                rtype
+            } else {
+                return Err(Error {
+                    position,
+                    message: format!("Unknown function '{}'", name),
+                });
+            }
+        }
+        ast::Expr::Select {
+            position,
+            ref mut condition,
+            ref mut if_true,
+            ref mut if_false,
+        } => {
+            tc_expression(context, condition)?;
+            tc_expression(context, if_true)?;
+            tc_expression(context, if_false)?;
+            if condition.type_ != Some(ast::Type::I32) {
+                return Err(Error {
+                    position,
+                    message: "Condition of select has to be of type i32".into(),
+                });
+            }
+            if if_true.type_ != if_false.type_ {
+                return Err(Error {
+                    position,
+                    message: "Types of select branches differ".into(),
+                });
+            }
+            if if_true.type_.is_none() {
+                return Err(Error {
+                    position,
+                    message: "Types of select branches cannot be void".into(),
+                });
+            }
+            if_true.type_
+        }
     };
     Ok(())
 }
@@ -246,3 +313,13 @@ fn tc_mem_location<'a>(
     }
     Ok(())
 }
+
+fn builtin_function_types(name: &str) -> Option<(&'static [ast::Type], Option<ast::Type>)> {
+    use ast::Type::*;
+    let types: (&'static [ast::Type], Option<ast::Type>) = match name {
+        "sqrt" => (&[F32], Some(F32)),
+        "abs" => (&[F32], Some(F32)),
+        _ => return None,
+    };
+    Some(types)
+}

trainride.hw

@@ -0,0 +1,26 @@
+import "uw8.ram" memory(2);
+import "uw8.time" global mut time: i32;
+
+export fn tic() {
+  let i: i32;
+  let defer t = time as f32 / 1000 as f32;
+  loop pixels {
+    let defer x = (i % 320 - 160) as f32;
+    let defer y = (i / 320) as f32 - 128.5;
+    let defer z = t + 20 as f32 / sqrt(x*x + y*y);
+    let defer z_int = z as i32;
+    let defer q = select(z_int % 9 >= 6, z, (z_int - z_int % 9 + 6) as f32);
+    let defer w = 9 as f32 / y + t;
+    let defer s = q - t;
+    let defer m = x * s / 50 as f32;
+
+    i?120 = select(y > 0 as f32 & w < q,
+              select(abs(x * (w - t)) < 9 as f32, 15, 7) - w as i32 % 2,
+              select(y * s > -99 as f32 / (m * m + 1 as f32),
+                select(q == z, z_int % 2, 3),
+                12 + (y / 23 as f32) as i32
+              )
+            ) * 16;
+    branch_if (i := i + 1) < 320*256: pixels;
+  }
+}