Deprecate optional '?' postfix operator

22 files changed, 58 insertions, 100 deletions

diff --git a/CHANGES.md b/CHANGES.md
index 1e0b840e..dd015b5f 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,6 +1,6 @@
 # Version History
 
-## v0.4
+## v1.0
 - Tomo libraries are now installed to `$TOMO_PATH/lib/tomo_vX.Y/module_vZ.W`
   instead of `$TOMO_PATH/share/tomo_vX.Y/installed/module_vZ.W`
 - Core libraries are no longer shipped with the compiler, they have moved to
@@ -14,6 +14,8 @@
   - Tables now have `and`, `or`, `xor`, and `-` (minus) metamethods.
 - Deprecated `extern` keyword for declaring external symbols from C.
   - Use `C_code` instead.
+- Deprecated the postfix `?` to make values optional.
+  - Explicitly optional values can be declared as `my_var : T? = value`.
 - Added a `--format` flag to the `tomo` binary that autoformats your code
   (currently unstable, do not rely on it just yet).
 - Standardized text methods for Unicode encodings:
diff --git a/src/ast.c b/src/ast.c
index 4dfd7d0f..0dcda5dc 100644
--- a/src/ast.c
+++ b/src/ast.c
@@ -269,7 +269,6 @@ Text_t ast_to_sexp(ast_t *ast) {
         T(LangDef, "(LangDef \"", data.name, "\" ", ast_to_sexp(data.namespace), ")");
         T(Index, "(Index ", ast_to_sexp(data.indexed), " ", ast_to_sexp(data.index), ")");
         T(FieldAccess, "(FieldAccess ", ast_to_sexp(data.fielded), " \"", data.field, "\")");
-        T(Optional, "(Optional ", ast_to_sexp(data.value), ")");
         T(NonOptional, "(NonOptional ", ast_to_sexp(data.value), ")");
         T(DocTest, "(DocTest ", ast_to_sexp(data.expr), optional_sexp("expected", data.expected), ")");
         T(Assert, "(Assert ", ast_to_sexp(data.expr), " ", optional_sexp("message", data.message), ")");
@@ -655,10 +654,6 @@ void ast_visit(ast_t *ast, void (*visitor)(ast_t *, void *), void *userdata) {
         ast_visit(Match(ast, FieldAccess)->fielded, visitor, userdata);
         return;
     }
-    case Optional: {
-        ast_visit(Match(ast, Optional)->value, visitor, userdata);
-        return;
-    }
     case NonOptional: {
         ast_visit(Match(ast, NonOptional)->value, visitor, userdata);
         return;
diff --git a/src/ast.h b/src/ast.h
index 53685b28..90191219 100644
--- a/src/ast.h
+++ b/src/ast.h
@@ -269,7 +269,6 @@ typedef enum {
     LangDef,
     Index,
     FieldAccess,
-    Optional,
     NonOptional,
     DocTest,
     Assert,
@@ -438,7 +437,7 @@ struct ast_s {
         } FieldAccess;
         struct {
             ast_t *value;
-        } Optional, NonOptional;
+        } NonOptional;
         struct {
             ast_t *expr, *expected;
             bool skip_source : 1;
diff --git a/src/compile/expressions.c b/src/compile/expressions.c
index cd244fec..f4326b00 100644
--- a/src/compile/expressions.c
+++ b/src/compile/expressions.c
@@ -113,7 +113,6 @@ Text_t compile(env_t *env, ast_t *ast) {
     }
     case HeapAllocate:
     case StackReference: return compile_typed_allocation(env, ast, get_type(env, ast));
-    case Optional: return compile_optional(env, ast);
     case NonOptional: return compile_non_optional(env, ast);
     case Power:
     case Multiply:
diff --git a/src/compile/functions.c b/src/compile/functions.c
index e2fa8a11..5f6f7e91 100644
--- a/src/compile/functions.c
+++ b/src/compile/functions.c
@@ -552,10 +552,6 @@ static void add_closed_vars(Table_t *closed_vars, env_t *enclosing_scope, env_t
         add_closed_vars(closed_vars, enclosing_scope, env, Match(ast, FieldAccess)->fielded);
         break;
     }
-    case Optional: {
-        add_closed_vars(closed_vars, enclosing_scope, env, Match(ast, Optional)->value);
-        break;
-    }
     case NonOptional: {
         add_closed_vars(closed_vars, enclosing_scope, env, Match(ast, NonOptional)->value);
         break;
diff --git a/src/compile/optionals.c b/src/compile/optionals.c
index 86b4f771..d74f0f31 100644
--- a/src/compile/optionals.c
+++ b/src/compile/optionals.c
@@ -113,13 +113,6 @@ Text_t check_none(type_t *t, Text_t value) {
 }
 
 public
-Text_t compile_optional(env_t *env, ast_t *ast) {
-    ast_t *value = Match(ast, Optional)->value;
-    Text_t value_code = compile(env, value);
-    return promote_to_optional(get_type(env, value), value_code);
-}
-
-public
 Text_t compile_non_optional(env_t *env, ast_t *ast) {
     ast_t *value = Match(ast, NonOptional)->value;
     if (value->tag == Index && Match(value, Index)->index != NULL) return compile_indexing(env, value, true);
diff --git a/src/compile/optionals.h b/src/compile/optionals.h
index d30aaefb..28ee25b9 100644
--- a/src/compile/optionals.h
+++ b/src/compile/optionals.h
@@ -11,5 +11,4 @@ Text_t optional_into_nonnone(type_t *t, Text_t value);
 Text_t promote_to_optional(type_t *t, Text_t code);
 Text_t compile_none(type_t *t);
 Text_t check_none(type_t *t, Text_t value);
-Text_t compile_optional(env_t *env, ast_t *ast);
 Text_t compile_non_optional(env_t *env, ast_t *ast);
diff --git a/src/formatter/formatter.c b/src/formatter/formatter.c
index a07b903d..69c1a213 100644
--- a/src/formatter/formatter.c
+++ b/src/formatter/formatter.c
@@ -269,10 +269,6 @@ OptionalText_t format_inline_code(ast_t *ast, Table_t comments) {
         ast_t *val = Match(ast, StackReference)->value;
         return Texts("&", must(termify_inline(val, comments)));
     }
-    /*inline*/ case Optional: {
-        ast_t *val = Match(ast, Optional)->value;
-        return Texts(must(termify_inline(val, comments)), "?");
-    }
     /*inline*/ case NonOptional: {
         ast_t *val = Match(ast, NonOptional)->value;
         return Texts(must(termify_inline(val, comments)), "!");
@@ -698,11 +694,6 @@ Text_t format_code(ast_t *ast, Table_t comments, Text_t indent) {
         ast_t *val = Match(ast, StackReference)->value;
         return Texts("&(", termify(val, comments, indent), ")");
     }
-    /*multiline*/ case Optional: {
-        if (inlined_fits) return inlined;
-        ast_t *val = Match(ast, Optional)->value;
-        return Texts(termify(val, comments, indent), "?");
-    }
     /*multiline*/ case NonOptional: {
         if (inlined_fits) return inlined;
         ast_t *val = Match(ast, NonOptional)->value;
diff --git a/src/parse/binops.c b/src/parse/binops.c
index 4676b249..dd1ac3c2 100644
--- a/src/parse/binops.c
+++ b/src/parse/binops.c
@@ -73,8 +73,7 @@ ast_t *parse_infix_expr(parse_ctx_t *ctx, const char *pos, int min_tightness) {
                 progress =
                     (false || (new_term = parse_index_suffix(ctx, key))
                      || (new_term = parse_method_call_suffix(ctx, key)) || (new_term = parse_field_suffix(ctx, key))
-                     || (new_term = parse_fncall_suffix(ctx, key)) || (new_term = parse_optional_suffix(ctx, key))
-                     || (new_term = parse_non_optional_suffix(ctx, key)));
+                     || (new_term = parse_fncall_suffix(ctx, key)) || (new_term = parse_non_optional_suffix(ctx, key)));
                 if (progress) key = new_term;
             }
             if (key && key->tag == Var) key = NULL;
diff --git a/src/parse/expressions.c b/src/parse/expressions.c
index 7410f678..3cb47669 100644
--- a/src/parse/expressions.c
+++ b/src/parse/expressions.c
@@ -54,10 +54,9 @@ ast_t *parse_reduction(parse_ctx_t *ctx, const char *pos) {
     ast_t *key = NewAST(ctx->file, pos, pos, Var, .name = op_str);
     for (bool progress = true; progress;) {
         ast_t *new_term;
-        progress =
-            (false || (new_term = parse_index_suffix(ctx, key)) || (new_term = parse_method_call_suffix(ctx, key))
-             || (new_term = parse_field_suffix(ctx, key)) || (new_term = parse_fncall_suffix(ctx, key))
-             || (new_term = parse_optional_suffix(ctx, key)) || (new_term = parse_non_optional_suffix(ctx, key)));
+        progress = (false || (new_term = parse_index_suffix(ctx, key))
+                    || (new_term = parse_method_call_suffix(ctx, key)) || (new_term = parse_field_suffix(ctx, key))
+                    || (new_term = parse_fncall_suffix(ctx, key)) || (new_term = parse_non_optional_suffix(ctx, key)));
         if (progress) key = new_term;
     }
     if (key && key->tag == Var) key = NULL;
@@ -98,8 +97,7 @@ ast_t *parse_heap_alloc(parse_ctx_t *ctx, const char *pos) {
 
     ast_t *ast = NewAST(ctx->file, start, pos, HeapAllocate, .value = val);
     for (;;) {
-        ast_t *next = parse_optional_suffix(ctx, ast);
-        if (!next) next = parse_non_optional_suffix(ctx, ast);
+        ast_t *next = parse_non_optional_suffix(ctx, ast);
         if (!next) break;
         ast = next;
     }
@@ -123,8 +121,7 @@ ast_t *parse_stack_reference(parse_ctx_t *ctx, const char *pos) {
 
     ast_t *ast = NewAST(ctx->file, start, pos, StackReference, .value = val);
     for (;;) {
-        ast_t *next = parse_optional_suffix(ctx, ast);
-        if (!next) next = parse_non_optional_suffix(ctx, ast);
+        ast_t *next = parse_non_optional_suffix(ctx, ast);
         if (!next) break;
         ast = next;
     }
@@ -212,7 +209,7 @@ ast_t *parse_term(parse_ctx_t *ctx, const char *pos) {
         progress =
             (false || (new_term = parse_index_suffix(ctx, term)) || (new_term = parse_method_call_suffix(ctx, term))
              || (new_term = parse_field_suffix(ctx, term)) || (new_term = parse_fncall_suffix(ctx, term))
-             || (new_term = parse_optional_suffix(ctx, term)) || (new_term = parse_non_optional_suffix(ctx, term)));
+             || (new_term = parse_non_optional_suffix(ctx, term)));
         if (progress) term = new_term;
     }
     return term;
diff --git a/src/parse/suffixes.c b/src/parse/suffixes.c
index 312f958f..7493a65d 100644
--- a/src/parse/suffixes.c
+++ b/src/parse/suffixes.c
@@ -25,13 +25,6 @@ ast_t *parse_field_suffix(parse_ctx_t *ctx, ast_t *lhs) {
     return NewAST(ctx->file, lhs->start, pos, FieldAccess, .fielded = lhs, .field = field);
 }
 
-ast_t *parse_optional_suffix(parse_ctx_t *ctx, ast_t *lhs) {
-    if (!lhs) return NULL;
-    const char *pos = lhs->end;
-    if (match(&pos, "?")) return NewAST(ctx->file, lhs->start, pos, Optional, .value = lhs);
-    else return NULL;
-}
-
 ast_t *parse_non_optional_suffix(parse_ctx_t *ctx, ast_t *lhs) {
     if (!lhs) return NULL;
     const char *pos = lhs->end;
diff --git a/src/parse/suffixes.h b/src/parse/suffixes.h
index da2f23a2..23ca7182 100644
--- a/src/parse/suffixes.h
+++ b/src/parse/suffixes.h
@@ -11,4 +11,3 @@ ast_t *parse_index_suffix(parse_ctx_t *ctx, ast_t *lhs);
 ast_t *parse_method_call_suffix(parse_ctx_t *ctx, ast_t *self);
 ast_t *parse_non_optional_suffix(parse_ctx_t *ctx, ast_t *lhs);
 ast_t *parse_optional_conditional_suffix(parse_ctx_t *ctx, ast_t *stmt);
-ast_t *parse_optional_suffix(parse_ctx_t *ctx, ast_t *lhs);
diff --git a/src/typecheck.c b/src/typecheck.c
index 64bf0fd8..b4798768 100644
--- a/src/typecheck.c
+++ b/src/typecheck.c
@@ -798,12 +798,6 @@ type_t *get_type(env_t *env, ast_t *ast) {
         default: return Type(PointerType, .pointed = get_type(env, value), .is_stack = true);
         }
     }
-    case Optional: {
-        ast_t *value = Match(ast, Optional)->value;
-        type_t *t = get_type(env, value);
-        if (t->tag == OptionalType) code_err(ast, "This value is already optional, it can't be converted to optional");
-        return Type(OptionalType, .type = t);
-    }
     case NonOptional: {
         ast_t *value = Match(ast, NonOptional)->value;
         type_t *t = get_type(env, value);
diff --git a/test/iterators.tm b/test/iterators.tm
index c48e572b..ed08f73d 100644
--- a/test/iterators.tm
+++ b/test/iterators.tm
@@ -3,17 +3,17 @@ struct Pair(x:Text, y:Text)
 
 func pairwise(strs:[Text] -> func(->Pair?))
     i := 1
-    return func()
+    return func(-> Pair?)
         i += 1
-        return Pair(strs[i-1] or return none, strs[i] or return none)?
+        return Pair(strs[i-1] or return none, strs[i] or return none)
 
 func range(first:Int, last:Int -> func(->Int?))
     i := first
-    return func()
+    return func(->Int?)
         if i > last
             return none
         i += 1
-        return (i-1)?
+        return (i-1)
 
 func main()
     values := ["A", "B", "C", "D"]
diff --git a/test/lists.tm b/test/lists.tm
index 05001f19..2342c570 100644
--- a/test/lists.tm
+++ b/test/lists.tm
@@ -162,23 +162,23 @@ func main()
 		= [1, 2, 3, 4, 5]
 
 	>> ["a", "b", "c"].find("b")
-	= 2?
+	= 2
 	>> ["a", "b", "c"].find("XXX")
 	= none
 
 	>> [10, 20].where(func(i:&Int) i.is_prime())
 	= none
 	>> [4, 5, 6].where(func(i:&Int) i.is_prime())
-	= 2?
+	= 2
 
 	do
 		>> nums := &[10, 20, 30, 40, 50]
 		>> nums.pop()
-		= 50?
+		= 50
 		>> nums[]
 		= [10, 20, 30, 40]
 		>> nums.pop(2)
-		= 20?
+		= 20
 		>> nums[]
 		= [10, 30, 40]
 		>> nums.clear()
diff --git a/test/nums.tm b/test/nums.tm
index 362f590f..1ca09d7b 100644
--- a/test/nums.tm
+++ b/test/nums.tm
@@ -51,7 +51,9 @@ func main()
 	= no
 
 	>> Num32.sqrt(16)
-	= Num32(4)?
+	= Num32(4)
+	>> Num32.sqrt(-1)
+	= none
 
 	>> (0.25).mix(10, 20)
 	= 12.5
diff --git a/test/optionals.tm b/test/optionals.tm
index 1f7d640e..dcec904d 100644
--- a/test/optionals.tm
+++ b/test/optionals.tm
@@ -57,28 +57,28 @@ func maybe_lambda(should_i:Bool-> func()?)
 
 func maybe_c_string(should_i:Bool->CString?)
     if should_i
-        return ("hi".as_c_string())?
+        return "hi".as_c_string()
     else
         return none
 
 func main()
-    >> 5?
-    = 5?
+    >> optional : Int? = 5
+    = 5
 
     >> if no
         x : Int? = none
         x
     else
         5
-    = 5?
+    = 5
 
-    >> 5? or -1
+    >> optional or -1
     = 5
 
-    >> 5? or fail("Non-none is falsey")
+    >> optional or fail("Non-none is falsey")
     = 5
 
-    >> 5? or exit("Non-none is falsey")
+    >> optional or exit("Non-none is falsey")
     = 5
 
     >> none_int : Int? = none
@@ -88,7 +88,7 @@ func main()
     do
         say("Ints:")
         >> yep := maybe_int(yes)
-        = 123?
+        = 123
         >> nope := maybe_int(no)
         = none
         >> if yep
@@ -102,7 +102,7 @@ func main()
     do
         say("Int64s:")
         >> yep := maybe_int64(yes)
-        = Int64(123)?
+        = Int64(123)
         >> nope := maybe_int64(no)
         = none
         >> if yep
@@ -116,7 +116,7 @@ func main()
     do
         say("Lists:")
         >> yep := maybe_list(yes)
-        = [10, 20, 30]?
+        = [10, 20, 30]
         >> nope := maybe_list(no)
         = none
         >> if yep
@@ -131,7 +131,7 @@ func main()
         say("...")
         say("Bools:")
         >> yep := maybe_bool(yes)
-        = no?
+        = no
         >> nope := maybe_bool(no)
         = none
         >> if yep
@@ -146,7 +146,7 @@ func main()
         say("...")
         say("Text:")
         >> yep := maybe_text(yes)
-        = "Hello"?
+        = "Hello"
         >> nope := maybe_text(no)
         = none
         >> if yep
@@ -161,7 +161,7 @@ func main()
         say("...")
         say("Nums:")
         >> yep := maybe_num(yes)
-        = 12.3?
+        = 12.3
         >> nope := maybe_num(no)
         = none
         >> if yep
@@ -191,7 +191,7 @@ func main()
         say("...")
         say("Structs:")
         >> yep := Struct.maybe(yes)
-        = Struct(x=123, y="hello")?
+        = Struct(x=123, y="hello")
         >> nope := Struct.maybe(no)
         = none
         >> if yep
@@ -206,7 +206,7 @@ func main()
         say("...")
         say("Enums:")
         >> yep := Enum.maybe(yes)
-        = Enum.Y(123)?
+        = Enum.Y(123)
         >> nope := Enum.maybe(no)
         = none
         >> if yep
@@ -221,7 +221,7 @@ func main()
         say("...")
         say("C Strings:")
         >> yep := maybe_c_string(yes)
-        = CString("hi")?
+        = CString("hi")
         >> nope := maybe_c_string(no)
         = none
         >> if yep
@@ -241,16 +241,16 @@ func main()
     = 123
 
     # Test comparisons, hashing, equality:
-    assert none != 5?
-    assert 5? == 5?
+    assert none != optional
+    assert optional == 5
     >> nones : {Int?=Bool} = {none=yes, none=yes}
     >> nones.keys
     = [none]
-    >> [5?, none, none, 6?].sorted()
+    >> [5, none, none, 6].sorted()
     = [none, none, 5, 6]
 
     do
-        >> value := if var := 5?
+        >> value := if var := optional
             var
         else
             0
@@ -264,7 +264,7 @@ func main()
         = 0
 
     do
-        >> opt := 5?
+        >> opt : Int? = 5
         >> if opt
             >> opt
         else
@@ -277,17 +277,17 @@ func main()
         else
             >> opt
 
-    >> not 5?
+    >> not optional
     = no
 
     >> nah : Int? = none
     >> not nah
     = yes
 
-    >> [Struct(5,"A")?, Struct(6,"B"), Struct(7,"C")]
-    = [Struct(x=5, y="A")?, Struct(x=6, y="B")?, Struct(x=7, y="C")?]
+    >> [none, Struct(5,"A"), Struct(6,"B"), Struct(7,"C")]
+    = [none, Struct(x=5, y="A"), Struct(x=6, y="B"), Struct(x=7, y="C")]
 
-    if 5? or no
+    if optional or no
         say("Binary op 'or' works with optionals")
     else
         fail("Failed to do binary op 'or' on optional")
diff --git a/test/paths.tm b/test/paths.tm
index d92d4623..22f79c7b 100644
--- a/test/paths.tm
+++ b/test/paths.tm
@@ -20,7 +20,7 @@ func main()
     >> tmpfile.write("Hello world")
     >> tmpfile.append("!")
     >> tmpfile.read()
-    = "Hello world!"?
+    = "Hello world!"
     >> tmpfile.read_bytes()!
     = [0x48, 0x65, 0x6C, 0x6C, 0x6F, 0x20, 0x77, 0x6F, 0x72, 0x6C, 0x64, 0x21]
     assert tmpdir.files().has(tmpfile)
diff --git a/test/reductions.tm b/test/reductions.tm
index 3ec2ef5e..15c3d454 100644
--- a/test/reductions.tm
+++ b/test/reductions.tm
@@ -2,7 +2,7 @@ struct Foo(x,y:Int)
 
 func main()
 	>> (+: [10, 20, 30])
-	= 60?
+	= 60
 
 	>> empty_ints : [Int]
 	>> (+: empty_ints)
@@ -15,10 +15,10 @@ func main()
 	= 0
 
 	>> (_max_: [3, 5, 2, 1, 4])
-	= 5?
+	= 5
 
 	>> (_max_.abs(): [1, -10, 5])
-	= -10?
+	= -10
 
 	>> (_max_: [Foo(0, 0), Foo(1, 0), Foo(0, 10)])!
 	= Foo(x=1, y=0)
diff --git a/test/serialization.tm b/test/serialization.tm
index e2fa38a3..0e5be1ae 100644
--- a/test/serialization.tm
+++ b/test/serialization.tm
@@ -62,7 +62,7 @@ func main()
         assert deserialize(bytes -> MyEnum) == obj
 
     do
-        >> obj := "Hello"?
+        >> obj : Text? = "Hello"
         >> bytes := obj.serialized()
         assert deserialize(bytes -> Text?) == obj
 
diff --git a/test/tables.tm b/test/tables.tm
index 587a02c8..66318f11 100644
--- a/test/tables.tm
+++ b/test/tables.tm
@@ -3,9 +3,9 @@ func main()
 	= {"one"=1, "two"=2}
 
 	>> t["one"]
-	= 1?
+	= 1
 	>> t["two"]
-	= 2?
+	= 2
 	>> t["???"]
 	= none
 	>> t["one"]!
@@ -33,16 +33,16 @@ func main()
 	= {"three"=3; fallback={"one"=1, "two"=2}}
 
 	>> t2["one"]
-	= 1?
+	= 1
 	>> t2["three"]
-	= 3?
+	= 3
 	>> t2["???"]
 	= none
 
 	>> t2.length
 	= 1
 	>> t2.fallback
-	= {"one"=1, "two"=2}?
+	= {"one"=1, "two"=2}
 
 	t2_str := ""
 	for k,v in t2
diff --git a/test/when.tm b/test/when.tm
index d18f5276..57de4c2c 100644
--- a/test/when.tm
+++ b/test/when.tm
@@ -15,4 +15,4 @@ func main()
     >> when n is 1 Int64(1)
     is 2 Int64(2)
     is 21 + 2 Int64(23)
-    = Int64(23)?
+    = Int64(23)