[Tolk] v0.6 syntax: fun, import, var, types on the right, etc.

Lots of changes, actually. Most noticeable are:
- traditional //comments
- #include -> import
- a rule "import what you use"
- ~ found -> !found (for -1/0)
- null() -> null
- is_null?(v) -> v == null
- throw is a keyword
- catch with swapped arguments
- throw_if, throw_unless -> assert
- do until -> do while
- elseif -> else if
- drop ifnot, elseifnot
- drop rarely used operators

A testing framework also appears here. All tests existed earlier,
but due to significant syntax changes, their history is useless.

tolk-tester/tests/allow_post_modification.tolk

@@ -0,0 +1,108 @@
+fun unsafe_tuple<X>(x: X): tuple
+    asm "NOP";
+
+fun inc(x: int, y: int): (int, int) {
+  return (x + y, y * 10);
+}
+fun ~inc(x: int, y: int): (int, int) {
+  (x, y) = inc(x, y);
+  return (x, y);
+}
+
+fun ~incWrap(x: int, y: int): (int, int) {
+  return ~inc(x, y);
+}
+
+@method_id(11)
+fun test_return(x: int): (int, int, int, int, int, int, int) {
+  return (x, x~incWrap(x / 20), x, x = x * 2, x, x += 1, x);
+}
+
+@method_id(12)
+fun test_assign(x: int): (int, int, int, int, int, int, int) {
+  var (x1: int, x2: int, x3: int, x4: int, x5: int, x6: int, x7: int) = (x, x~inc(x / 20), x, x=x*2, x, x+=1, x);
+  return (x1, x2, x3, x4, x5, x6, x7);
+}
+
+@method_id(13)
+fun test_tuple(x: int): tuple {
+  var t: tuple = unsafe_tuple([x, x~incWrap(x / 20), x, x = x * 2, x, x += 1, x]);
+  return t;
+}
+
+@method_id(14)
+fun test_tuple_assign(x: int): (int, int, int, int, int, int, int) {
+  var [x1: int, x2: int, x3: int, x4: int, x5: int, x6: int, x7: int] = [x, x~inc(x / 20), x, x = x * 2, x, x += 1, x];
+  return (x1, x2, x3, x4, x5, x6, x7);
+}
+
+fun foo1(x1: int, x2: int, x3: int, x4: int, x5: int, x6: int, x7: int): (int, int, int, int, int, int, int) {
+  return (x1, x2, x3, x4, x5, x6, x7);
+}
+
+@method_id(15)
+fun test_call_1(x: int): (int, int, int, int, int, int, int) {
+  return foo1(x, x~inc(x / 20), x, x = x * 2, x, x += 1, x);
+}
+
+fun foo2(x1: int, x2: int, x3456: (int, int, int, int), x7: int): (int, int, int, int, int, int, int) {
+  var (x3: int, x4: int, x5: int, x6: int) = x3456;
+  return (x1, x2, x3, x4, x5, x6, x7);
+}
+
+@method_id(16)
+fun test_call_2(x: int): (int, int, int, int, int, int, int) {
+  return foo2(x, x~incWrap(x / 20), (x, x = x * 2, x, x += 1), x);
+}
+
+fun asm_func(x1: int, x2: int, x3: int, x4: int, x5: int, x6: int, x7: int): (int, int, int, int, int, int, int)
+asm
+        (x4 x5 x6 x7 x1 x2 x3->0 1 2 3 4 5 6) "NOP";
+
+@method_id(17)
+fun test_call_asm_old(x: int): (int, int, int, int, int, int, int) {
+  return asm_func(x, x += 1, x, x, x~inc(x / 20), x, x = x * 2);
+}
+
+@method_id(18)
+fun test_call_asm_new(x: int): (int, int, int, int, int, int, int) {
+  return asm_func(x, x~incWrap(x / 20), x, x = x * 2, x, x += 1, x);
+}
+
+global xx: int;
+@method_id(19)
+fun test_global(x: int): (int, int, int, int, int, int, int) {
+  xx = x;
+  return (xx, xx~incWrap(xx / 20), xx, xx = xx * 2, xx, xx += 1, xx);
+}
+
+@method_id(20)
+fun test_if_else(x: int): (int, int, int, int, int) {
+  if (x > 10) {
+    return (x~inc(8), x + 1, x = 1, x <<= 3, x);
+  } else {
+    xx = 9;
+    return (x, x~inc(-4), x~inc(-1), x >= 1, x = x + xx);
+  }
+}
+
+fun main() {
+}
+
+/**
+    method_id | in  | out
+@testcase | 11 | 100 | 100 50 105 210 210 211 211
+@testcase | 12 | 100 | 100 50 105 210 210 211 211
+@testcase | 13 | 100 | [ 100 50 105 210 210 211 211 ]
+@testcase | 14 | 100 | 100 50 105 210 210 211 211
+@testcase | 15 | 100 | 100 50 105 210 210 211 211
+@testcase | 16 | 100 | 100 50 105 210 210 211 211
+@testcase | 17 | 100 | 101 50 106 212 100 101 101
+@testcase | 18 | 100 | 210 210 211 211 100 50 105
+@testcase | 19 | 100 | 100 50 105 210 210 211 211
+@testcase | 20 | 80  | 80 89 1 8 8
+@testcase | 20 | 9   | 9 -40 -10 -1 13
+
+@fif_codegen_avoid ~incWrap
+@code_hash 97139400653362069936987769894397430077752335662822462908581556703209313861576
+*/