Add a `repeat` keyword

7 files changed, 36 insertions, 5 deletions

diff --git a/ast.c b/ast.c
index 8eca3147..65a8f405 100644
--- a/ast.c
+++ b/ast.c
@@ -137,6 +137,7 @@ CORD ast_to_xml(ast_t *ast)
     T(For, "<For>%r%r%r%r%r</For>", ast_list_to_xml(data.vars), optional_tagged("iterable", data.iter),
       optional_tagged("body", data.body), optional_tagged("empty", data.empty))
     T(While, "<While>%r%r</While>", optional_tagged("condition", data.condition), optional_tagged("body", data.body))
+    T(Repeat, "<Repeat>%r</Repeat>", optional_tagged("body", data.body))
     T(If, "<If>%r%r%r</If>", optional_tagged("condition", data.condition), optional_tagged("body", data.body), optional_tagged("else", data.else_body))
     T(When, "<When><subject>%r</subject>%r%r</When>", ast_to_xml(data.subject), when_clauses_to_xml(data.clauses), optional_tagged("else", data.else_body))
     T(Reduction, "<Reduction>%r%r</Reduction>", optional_tagged("iterable", data.iter),
diff --git a/ast.h b/ast.h
index 5d7f87d2..6546dd2d 100644
--- a/ast.h
+++ b/ast.h
@@ -133,7 +133,7 @@ typedef enum {
     FunctionDef, Lambda,
     FunctionCall, MethodCall,
     Block,
-    For, While, If, When,
+    For, While, If, When, Repeat,
     Reduction,
     Skip, Stop, Pass,
     Defer,
@@ -256,6 +256,9 @@ struct ast_s {
             ast_t *condition, *body;
         } While;
         struct {
+            ast_t *body;
+        } Repeat;
+        struct {
             ast_t *condition, *body, *else_body;
         } If;
         struct {
diff --git a/compile.c b/compile.c
index 0ab4fa41..91abbef8 100644
--- a/compile.c
+++ b/compile.c
@@ -1056,6 +1056,23 @@ CORD compile_statement(env_t *env, ast_t *ast)
             loop = CORD_all(loop, "\n", loop_ctx.stop_label, ":;");
         return loop;
     }
+    case Repeat: {
+        ast_t *body = Match(ast, Repeat)->body;
+        env_t *scope = fresh_scope(env);
+        loop_ctx_t loop_ctx = (loop_ctx_t){
+            .loop_name="repeat",
+            .deferred=scope->deferred,
+            .next=env->loop_ctx,
+        };
+        scope->loop_ctx = &loop_ctx;
+        CORD body_code = compile_statement(scope, body);
+        if (loop_ctx.skip_label)
+            body_code = CORD_all(body_code, "\n", loop_ctx.skip_label, ": continue;");
+        CORD loop = CORD_all("for (;;) {\n\t", body_code, "\n}");
+        if (loop_ctx.stop_label)
+            loop = CORD_all(loop, "\n", loop_ctx.stop_label, ":;");
+        return loop;
+    }
     case For: {
         auto for_ = Match(ast, For);
 
@@ -3385,7 +3402,7 @@ CORD compile(env_t *env, ast_t *ast)
     case Defer: code_err(ast, "Compiling 'defer' as expression!");
     case Extern: code_err(ast, "Externs are not supported as expressions");
     case TableEntry: code_err(ast, "Table entries should not be compiled directly");
-    case Declare: case Assign: case UpdateAssign: case For: case While: case StructDef: case LangDef:
+    case Declare: case Assign: case UpdateAssign: case For: case While: case Repeat: case StructDef: case LangDef:
     case EnumDef: case FunctionDef: case Skip: case Stop: case Pass: case Return: case DocTest: case PrintStatement:
         code_err(ast, "This is not a valid expression");
     default: case Unknown: code_err(ast, "Unknown AST");
diff --git a/docs/threads.md b/docs/threads.md
index ab0ce399..68fdf7d7 100644
--- a/docs/threads.md
+++ b/docs/threads.md
@@ -28,7 +28,7 @@ A new `Thread` object representing the created thread.
 >> jobs := |Int|
 >> results := |Int|
 >> thread := Thread.new(func():
-    while yes:
+    repeat:
         input := jobs:get()
         results:give(input + 10
 )
diff --git a/parse.c b/parse.c
index 2ea8cd78..7af03a16 100644
--- a/parse.c
+++ b/parse.c
@@ -122,6 +122,7 @@ static PARSER(parse_parens);
 static PARSER(parse_pass);
 static PARSER(parse_path);
 static PARSER(parse_reduction);
+static PARSER(parse_repeat);
 static PARSER(parse_return);
 static PARSER(parse_say);
 static PARSER(parse_set);
@@ -1222,6 +1223,14 @@ PARSER(parse_while) {
     return NewAST(ctx->file, start, pos, While, .condition=condition, .body=body);
 }
 
+PARSER(parse_repeat) {
+    // repeat: [<indent>] body
+    const char *start = pos;
+    if (!match_word(&pos, "repeat")) return NULL;
+    ast_t *body = expect(ctx, start, &pos, parse_block, "I expected a body for this 'repeat'"); 
+    return NewAST(ctx->file, start, pos, Repeat, .body=body);
+}
+
 PARSER(parse_heap_alloc) {
     const char *start = pos;
     if (!match(&pos, "@")) return NULL;
@@ -1874,6 +1883,7 @@ PARSER(parse_extended_expr) {
         || (expr=optional(ctx, &pos, parse_while))
         || (expr=optional(ctx, &pos, parse_if))
         || (expr=optional(ctx, &pos, parse_when))
+        || (expr=optional(ctx, &pos, parse_repeat))
         || (expr=optional(ctx, &pos, parse_do))
         )
         return expr;
diff --git a/test/threads.tm b/test/threads.tm
index 2ac2b679..8fa61778 100644
--- a/test/threads.tm
+++ b/test/threads.tm
@@ -27,7 +27,7 @@ func main():
     results := |:Int; max_size|
     >> thread := Thread.new(func():
         !! In another thread!
-        while yes:
+        repeat:
             >> got := jobs:get()
             when got is Increment(x):
                 >> results:give(x+1)
diff --git a/typecheck.c b/typecheck.c
index bff7d080..7cc081de 100644
--- a/typecheck.c
+++ b/typecheck.c
@@ -1229,7 +1229,7 @@ type_t *get_type(env_t *env, ast_t *ast)
         }
     }
 
-    case While: case For: return Type(VoidType);
+    case While: case Repeat: case For: return Type(VoidType);
     case InlineCCode: {
         auto inline_code = Match(ast, InlineCCode);
         if (inline_code->type)