Clean up and fix issue with `if var := val` statements. Previous

implementation was kinda janky, but the new one is more robust and
simple.

4 files changed, 40 insertions, 33 deletions

diff --git a/examples/http-server/http-server.tm b/examples/http-server/http-server.tm
index 89141c32..8e8aff7e 100644
--- a/examples/http-server/http-server.tm
+++ b/examples/http-server/http-server.tm
@@ -52,7 +52,7 @@ func serve(port:Int32, handler:func(request:HTTPRequest -> HTTPResponse), num_th
         int opt = 1;
         if (setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt)) < 0)
             err(1, "Couldn't set socket option");
-            
+
         struct sockaddr_in addr = {AF_INET, htons(@port), INADDR_ANY};
         if (bind(s, (struct sockaddr*)&addr, sizeof(addr)) < 0)
             err(1, "Couldn't bind to socket");
diff --git a/src/compile/conditionals.c b/src/compile/conditionals.c
index 6071b6c4..23d2a177 100644
--- a/src/compile/conditionals.c
+++ b/src/compile/conditionals.c
@@ -36,19 +36,38 @@ Text_t compile_if_statement(env_t *env, ast_t *ast) {
     DeclareMatch(if_, ast, If);
     ast_t *condition = if_->condition;
     if (condition->tag == Declare) {
-        if (Match(condition, Declare)->value == NULL) code_err(condition, "This declaration must have a value");
+        DeclareMatch(decl, condition, Declare);
+        if (decl->value == NULL) code_err(condition, "This declaration must have a value");
+
         env_t *truthy_scope = fresh_scope(env);
-        Text_t code = Texts("IF_DECLARE(", compile_statement(truthy_scope, condition), ", ");
+        ast_t *var = decl->var;
+        type_t *var_type = get_type(truthy_scope, decl->value);
+
+        const char *name = Match(var, Var)->name;
         bind_statement(truthy_scope, condition);
-        ast_t *var = Match(condition, Declare)->var;
-        code = Texts(code, compile_condition(truthy_scope, var), ", ");
-        type_t *cond_t = get_type(truthy_scope, var);
-        if (cond_t->tag == OptionalType) {
-            set_binding(truthy_scope, Match(var, Var)->name, Match(cond_t, OptionalType)->type,
-                        optional_into_nonnone(cond_t, compile(truthy_scope, var)));
+
+        Text_t code = Texts("if (true) {\n", compile_statement(env, condition), //
+                            "if (", compile_condition(truthy_scope, var), ")");
+
+        env_t *nonnull_scope = truthy_scope;
+        if (var_type->tag == OptionalType) {
+            nonnull_scope = fresh_scope(truthy_scope);
+            set_binding(nonnull_scope, name, Match(var_type, OptionalType)->type,
+                        optional_into_nonnone(var_type, compile(truthy_scope, var)));
         }
-        code = Texts(code, compile_statement(truthy_scope, if_->body), ")");
-        if (if_->else_body) code = Texts(code, "\nelse ", compile_statement(env, if_->else_body));
+
+        code = Texts(code, compile_block(nonnull_scope, if_->body));
+
+        if (if_->else_body) {
+            Text_t label = Texts("_falsey_", String((int64_t)(ast->start - ast->file->text)));
+            code = Texts(code, "else goto ", label,
+                         ";\n"
+                         "} else {\n",
+                         label, ":;\n", compile_inline_block(env, if_->else_body), "}\n");
+        } else {
+            code = Texts(code, "}\n");
+        }
+
         return code;
     } else {
         Text_t code = Texts("if (", compile_condition(env, condition), ")");
diff --git a/src/compile/optionals.c b/src/compile/optionals.c
index 1cd86c29..b3d94005 100644
--- a/src/compile/optionals.c
+++ b/src/compile/optionals.c
@@ -92,21 +92,20 @@ Text_t check_none(type_t *t, Text_t value) {
     t = Match(t, OptionalType)->type;
     // NOTE: these use statement expressions ({...;}) because some compilers
     // complain about excessive parens around equality comparisons
-    if (t->tag == PointerType || t->tag == FunctionType || t->tag == CStringType)
-        return Texts("({", value, " == NULL;})");
-    else if (t == PATH_TYPE) return Texts("({(", value, ").type.$tag == PATH_NONE;})");
-    else if (t == PATH_TYPE_TYPE) return Texts("({(", value, ").$tag == PATH_NONE;})");
-    else if (t->tag == BigIntType) return Texts("({(", value, ").small == 0;})");
-    else if (t->tag == ClosureType) return Texts("({(", value, ").fn == NULL;})");
+    if (t->tag == PointerType || t->tag == FunctionType || t->tag == CStringType) return Texts("(", value, " == NULL)");
+    else if (t == PATH_TYPE) return Texts("((", value, ").type.$tag == PATH_NONE)");
+    else if (t == PATH_TYPE_TYPE) return Texts("((", value, ").$tag == PATH_NONE)");
+    else if (t->tag == BigIntType) return Texts("((", value, ").small == 0)");
+    else if (t->tag == ClosureType) return Texts("((", value, ").fn == NULL)");
     else if (t->tag == NumType)
         return Texts(Match(t, NumType)->bits == TYPE_NBITS64 ? "Num$isnan(" : "Num32$isnan(", value, ")");
-    else if (t->tag == ListType) return Texts("({(", value, ").length < 0;})");
-    else if (t->tag == TableType || t->tag == SetType) return Texts("({(", value, ").entries.length < 0;})");
-    else if (t->tag == BoolType) return Texts("({(", value, ") == NONE_BOOL;})");
-    else if (t->tag == TextType) return Texts("({(", value, ").length < 0;})");
+    else if (t->tag == ListType) return Texts("((", value, ").length < 0)");
+    else if (t->tag == TableType || t->tag == SetType) return Texts("((", value, ").entries.length < 0)");
+    else if (t->tag == BoolType) return Texts("((", value, ") == NONE_BOOL)");
+    else if (t->tag == TextType) return Texts("((", value, ").length < 0)");
     else if (t->tag == IntType || t->tag == ByteType || t->tag == StructType) return Texts("(", value, ").is_none");
     else if (t->tag == EnumType) {
-        if (enum_has_fields(t)) return Texts("({(", value, ").$tag == 0;})");
+        if (enum_has_fields(t)) return Texts("((", value, ").$tag == 0)");
         else return Texts("((", value, ") == 0)");
     }
     print_err("Optional check not implemented for: ", type_to_str(t));
diff --git a/src/stdlib/util.h b/src/stdlib/util.h
index a789c5f0..1530bd9e 100644
--- a/src/stdlib/util.h
+++ b/src/stdlib/util.h
@@ -21,17 +21,6 @@
         &var;                                                                                                          \
     })
 
-#define IF_DECLARE(decl, expr, block)                                                                                  \
-    if (({                                                                                                             \
-            decl;                                                                                                      \
-            expr ? ({                                                                                                  \
-                block;                                                                                                 \
-                1;                                                                                                     \
-            })                                                                                                         \
-                 : 0;                                                                                                  \
-        })) {                                                                                                          \
-    }
-
 #define WHEN(type, subj, var, body)                                                                                    \
     {                                                                                                                  \
         type var = subj;                                                                                               \