Jm/elseif break continue

FIXME.md

@@ -0,0 +1,39 @@
+# FIXME
+
+Commits on this branch (main..HEAD), in order:
+
+- 57fc54c Add break and continue statements
+- a22c056 Fix nested match codegen panic
+- 978f14b Use break in sort example
+- d9e0aa3 Add for loop support with range syntax
+- a6fe98f Add string comparison operators == and !=
+- 9b746d3 Add index syntax [] and change generics to <>
+- aa09a93 check tests properly
+- 7555204 Change default target name from capable
+- f64de33 Remove outdated plan file
+- 4bd4f97 remove outdated progress file
+- 529b9ed move docs
+- 4c6e29e Simple ok+err handlers
+- f0b3345 Add Vec indexing syntax and fix for-loop range parsing
+- c167d11 Move Result<T, E> enum from compiler builtin to stdlib
+- 2f28e94 [WIP] Move Result methods from compiler special-case to stdlib
+- 993e805 Fix some stuff
+- 7416ad8 Fix loop linearity, indexing constraints, and call conv
+- 3f2aca3 Add docs and TODO list
+- fc93b87 Add never type and Vec<T> specializations
+- d925d5b Add top-level defer statement
+- 4763187 Make defer scope-based
+- a29d59b Improve net listener and string helpers
+- c53e84d Add if let statement sugar
+- 15276b0 Add for {} infinite loop sugar
+- 4ee669e Add char literals and string helpers
+- 48b63f0 stdlib: flesh out string/vec helpers
+- 1df8699 codegen: lower struct returns via sret/result-out
+- 29effac docs: describe ABI lowering for struct returns
+
+Fixes applied from review:
+
+- Allow user-defined `string` type names now that `string` is userland; update reserved-name test to `i32`.
+- Support sret lowering in runtime wrapper emission to avoid ABI mismatches.
+- Use return lowering in `try` error path to avoid returning wrong signature.
+- Initialize zero values for non-opaque structs to avoid null deref when building Result payloads.

TODO.md

@@ -0,0 +1,4 @@
+Done:
+- Result<T, E> + is_ok/is_err/ok/err/unwrap_* implemented in stdlib (panic uses never type).
+- Stdlib APIs updated to use Vec<T> (compiler maps Vec<u8>/Vec<i32>/Vec<string> to VecU8/VecI32/VecString).
+- Codex reviewed Claude-generated commits.

capc/src/abi.rs

@@ -10,10 +10,7 @@ pub enum AbiType {
     Bool,
     Handle,
     Ptr,
-    String,
     Result(Box<AbiType>, Box<AbiType>),
-    /// ABI-only return lowering for `Result<String, i32>`.
-    ResultString,
     /// ABI-only return lowering for `Result<T, E>` where out params are used.
     ResultOut(Box<AbiType>, Box<AbiType>),
 }

capc/src/ast.rs

@@ -141,9 +141,13 @@ pub struct Block {
 pub enum Stmt {
     Let(LetStmt),
     Assign(AssignStmt),
+    Defer(DeferStmt),
     Return(ReturnStmt),
+    Break(BreakStmt),
+    Continue(ContinueStmt),
     If(IfStmt),
     While(WhileStmt),
+    For(ForStmt),
     Expr(ExprStmt),
 }
 
@@ -161,6 +165,16 @@ pub struct ReturnStmt {
     pub span: Span,
 }
 
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct BreakStmt {
+    pub span: Span,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct ContinueStmt {
+    pub span: Span,
+}
+
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct IfStmt {
     pub cond: Expr,
@@ -176,6 +190,15 @@ pub struct WhileStmt {
     pub span: Span,
 }
 
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct ForStmt {
+    pub var: Ident,
+    pub start: Expr,
+    pub end: Expr,
+    pub body: Block,
+    pub span: Span,
+}
+
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct ExprStmt {
     pub expr: Expr,
@@ -189,14 +212,24 @@ pub struct AssignStmt {
     pub span: Span,
 }
 
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct DeferStmt {
+    pub expr: Expr,
+    pub span: Span,
+}
+
 impl Stmt {
     pub fn span(&self) -> Span {
         match self {
             Stmt::Let(s) => s.span,
             Stmt::Assign(s) => s.span,
+            Stmt::Defer(s) => s.span,
             Stmt::Return(s) => s.span,
+            Stmt::Break(s) => s.span,
+            Stmt::Continue(s) => s.span,
             Stmt::If(s) => s.span,
             Stmt::While(s) => s.span,
+            Stmt::For(s) => s.span,
             Stmt::Expr(s) => s.span,
         }
     }
@@ -209,6 +242,7 @@ pub enum Expr {
     Call(CallExpr),
     MethodCall(MethodCallExpr),
     FieldAccess(FieldAccessExpr),
+    Index(IndexExpr),
     StructLiteral(StructLiteralExpr),
     Unary(UnaryExpr),
     Binary(BinaryExpr),
@@ -288,6 +322,13 @@ pub struct FieldAccessExpr {
     pub span: Span,
 }
 
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct IndexExpr {
+    pub object: Box<Expr>,
+    pub index: Box<Expr>,
+    pub span: Span,
+}
+
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct MethodCallExpr {
     pub receiver: Box<Expr>,

capc/src/codegen/abi_quirks.rs

@@ -1,35 +1,38 @@
 //! ABI quirks and lowering helpers.
 //!
 //! These helpers are the single source of truth for the special-case ABI
-//! shapes we use to lower `Result` values (ResultString and ResultOut).
+//! shapes we use to lower `Result` values (ResultOut).
 
 use crate::abi::AbiType;
 
 use super::FnSig;
 
-/// ResultString ABI uses a u64 length slot across targets.
-pub fn result_string_len_bytes() -> u32 {
-    8
-}
-
-/// Return true if the ABI type is lowered as ResultString.
-pub fn is_result_string(ty: &AbiType) -> bool {
-    matches!(ty, AbiType::ResultString)
-}
-
 /// Return true if the ABI type is lowered using ResultOut parameters.
 pub fn is_result_out(ty: &AbiType) -> bool {
     matches!(ty, AbiType::ResultOut(_, _))
 }
 
 /// Return true if the ABI type uses any Result lowering.
 pub fn is_result_lowering(ty: &AbiType) -> bool {
-    is_result_string(ty) || is_result_out(ty)
+    is_result_out(ty)
 }
 
-/// Return true if a signature mismatch is explained by Result lowering.
+fn is_sret_lowering(abi_sig: &FnSig, sig: &FnSig) -> bool {
+    if sig.ret != AbiType::Ptr || abi_sig.ret != AbiType::Unit {
+        return false;
+    }
+    if abi_sig.params.len() != sig.params.len() + 1 {
+        return false;
+    }
+    if abi_sig.params.first() != Some(&AbiType::Ptr) {
+        return false;
+    }
+    abi_sig.params[1..] == sig.params
+}
+
+/// Return true if a signature mismatch is explained by Result or sret lowering.
 pub fn abi_sig_requires_lowering(abi_sig: &FnSig, sig: &FnSig) -> bool {
-    abi_sig != sig && is_result_lowering(&abi_sig.ret)
+    abi_sig != sig && (is_result_lowering(&abi_sig.ret) || is_sret_lowering(abi_sig, sig))
 }
 
 /// Error message used when a layout is requested for a lowered Result ABI.
@@ -46,8 +49,3 @@ pub fn result_abi_mismatch_error() -> &'static str {
 pub fn result_out_params_error() -> &'static str {
     "result out params"
 }
-
-/// Error message used when ResultString lowering is requested but unsupported.
-pub fn result_string_params_error() -> &'static str {
-    "result abi"
-}