feat: add ++ concat operator and auto-invoke main

BUG-004: Add ++ operator for string and list concatenation across all
backends (interpreter, C, JS) with type checking and formatting support.

BUG-001: Auto-invoke top-level `let main = fn () => ...` when main is
a zero-parameter function, instead of just printing the function value.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
This commit is contained in:
2026-02-18 22:01:41 -05:00
parent bb0a288210
commit 61e1469845
9 changed files with 110 additions and 7 deletions

View File

@@ -730,10 +730,10 @@ impl CBackend {
}
// Check for string concatenation - use lux_string_concat instead of +
if matches!(op, BinaryOp::Add) {
if matches!(op, BinaryOp::Add | BinaryOp::Concat) {
let left_is_string = self.infer_expr_type(left).as_deref() == Some("LuxString");
let right_is_string = self.infer_expr_type(right).as_deref() == Some("LuxString");
if left_is_string || right_is_string {
if left_is_string || right_is_string || matches!(op, BinaryOp::Concat) {
return Ok(format!("lux_string_concat({}, {})", l, r));
}
}
@@ -2839,8 +2839,18 @@ impl CBackend {
}
}
// String concatenation for ++ and +
if matches!(op, BinaryOp::Add | BinaryOp::Concat) {
let left_is_string = self.infer_expr_type(left).as_deref() == Some("LuxString");
let right_is_string = self.infer_expr_type(right).as_deref() == Some("LuxString");
if left_is_string || right_is_string || matches!(op, BinaryOp::Concat) {
return Ok(format!("lux_string_concat({}, {})", l, r));
}
}
let op_str = match op {
BinaryOp::Add => "+",
BinaryOp::Concat => unreachable!("handled above"),
BinaryOp::Sub => "-",
BinaryOp::Mul => "*",
BinaryOp::Div => "/",

View File

@@ -954,12 +954,17 @@ impl JsBackend {
let r = self.emit_expr(right)?;
// Check for string concatenation
if matches!(op, BinaryOp::Add) {
if matches!(op, BinaryOp::Add | BinaryOp::Concat) {
if self.is_string_expr(left) || self.is_string_expr(right) {
return Ok(format!("({} + {})", l, r));
}
}
// ++ on lists: use .concat()
if matches!(op, BinaryOp::Concat) {
return Ok(format!("{}.concat({})", l, r));
}
let op_str = match op {
BinaryOp::Add => "+",
BinaryOp::Sub => "-",
@@ -974,6 +979,7 @@ impl JsBackend {
BinaryOp::Ge => ">=",
BinaryOp::And => "&&",
BinaryOp::Or => "||",
BinaryOp::Concat => unreachable!("handled above"),
BinaryOp::Pipe => {
// Pipe operator: x |> f becomes f(x)
return Ok(format!("{}({})", r, l));
@@ -2342,7 +2348,7 @@ impl JsBackend {
}
}
Expr::BinaryOp { op, left, right, .. } => {
matches!(op, BinaryOp::Add)
matches!(op, BinaryOp::Add | BinaryOp::Concat)
&& (self.is_string_expr(left) || self.is_string_expr(right))
}
_ => false,