tuple subscripts as overload, always generate TupAt for gear3 (#346)

* tuple indexes, broken until untyped templates

* compiles but not in C

* updated naming

* fix names again

* delete ahead of merge

* fix merge

* always generate TupAt, transform in gear3

* test output

lib/std/system.nim

@@ -75,8 +75,11 @@ proc low*[I, T](x: typedesc[array[I, T]]): I {.magic: "Low", noSideEffect.}
 proc high*[T: Ordinal|enum|range](x: typedesc[T]): T {.magic: "High", noSideEffect.}
 proc high*[I, T](x: typedesc[array[I, T]]): I {.magic: "High", noSideEffect.}
 
+proc `[]`*[T: tuple](x: T, i: int): untyped {.magic: "TupAt".}
 proc `[]`*[I, T](x: array[I, T], i: I): var T {.magic: "ArrAt".}
 proc `[]`*(x: cstring, i: int): var char {.magic: "Pat".}
+template `[]=`*[T: tuple](x: T, i: int, elem: typed) =
+  (x[i]) = elem
 template `[]=`*[I, T](x: array[I, T], i: I; elem: T) =
   (x[i]) = elem
 template `[]=`*(x: cstring, i: int; elem: char) =

src/gear3/expander.nim

@@ -246,13 +246,16 @@ proc traverseTupleBody(e: var EContext; c: var Cursor) =
   while c.kind != ParRi:
     if c.substructureKind == FldS:
       inc c # skip fld
+      e.offer c.symId
       skip c # skip name
       skip c # skip export marker
       skip c # skip pragmas
       genTupleField(e, c, counter)
       skip c # skip value
       skipParRi e, c
     else:
+      if c.kind == SymbolDef:
+        e.offer c.symId
       genTupleField(e, c, counter)
     inc counter
   wantParRi e, c
@@ -835,6 +838,16 @@ proc traverseExpr(e: var EContext; c: var Cursor) =
         e.dest.add tagToken("at", c.info)
         inc c
         inc nested
+      of TupAtX:
+        e.dest.add tagToken("dot", c.info)
+        inc c # skip tag
+        traverseExpr e, c # tuple
+        expectIntLit e, c
+        e.dest.add symToken(ithTupleField(pool.integers[c.intId]), c.info)
+        inc c # skip index
+        e.dest.addIntLit(0, c.info) # inheritance
+        e.dest.add c # add right paren
+        inc c # skip right paren
       of SufX:
         e.dest.add c
         inc c

src/nimony/magics.nim

@@ -88,7 +88,7 @@ type
     # not in Nim 2:
     mUnpack
     mDefaultObj, mDefaultTup
-    mArrAt, mPat
+    mArrAt, mPat, mTupAt
     mDeref
 
 declareMatcher parseMagic, TMagic, 1, 1
@@ -107,6 +107,7 @@ proc magicToTag*(m: TMagic): (string, int) =
   of mArrGet: res AtX
   of mArrAt: res ArrAtX
   of mPat: res PatX
+  of mTupAt: res TupAtX
   of mAsgn: res AsgnS
   of mAddI, mAddU, mAddF64: res AddX, TypedMagic
   of mSubI, mSubU, mSubF64: res SubX, TypedMagic

src/nimony/sem.nim

@@ -773,7 +773,7 @@ proc addFn(c: var SemContext; fn: FnCandidate; fnOrig: Cursor; args: openArray[I
         if n.kind == ParLe:
           if n.exprKind in {DefinedX, DeclaredX, CompilesX, TypeofX,
               LowX, HighX, AddrX, EnumToStrX, DefaultObjX, DefaultTupX,
-              ArrAtX, DerefX}:
+              ArrAtX, DerefX, TupAtX}:
             # magic needs semchecking after overloading
             result = MagicCallNeedsSemcheck
           else:
@@ -1505,19 +1505,22 @@ proc tryBuiltinDot(c: var SemContext; it: var Item; lhs: Item; fieldName: StrId;
     elif t.typeKind == TupleT:
       var tup = t
       inc tup
+      var i = 0
       while tup.kind != ParRi:
         let field = asLocal(tup)
         if field.name.kind == SymbolDef and sameIdent(field.name.symId, fieldName):
-          c.dest.add symToken(field.name.symId, info)
+          c.dest[exprStart] = parLeToken(TupAtX, info)
+          c.dest.addIntLit(i, info)
           it.typ = field.typ # will be fit later with commonType
           it.kind = FldY
           result = MatchedDotField
           break
         skip tup
+        inc i
       if result != MatchedDotField:
         c.dest.add identToken(fieldName, info)
         c.buildErr info, "undeclared field: " & pool.strings[fieldName]
-      c.dest.add intToken(pool.integers.getOrIncl(0), info)
+        c.dest.add intToken(pool.integers.getOrIncl(0), info)
     else:
       c.dest.add identToken(fieldName, info)
       c.buildErr info, "object type expected"
@@ -3791,6 +3794,13 @@ proc semTupAt(c: var SemContext; it: var Item) =
   takeToken c, it.n
   var tup = Item(n: it.n, typ: c.types.autoType)
   semExpr c, tup
+  if containsGenericParams(tup.typ):
+    # leave as is, probably enough to check tup.typ is a typevar
+    var index = Item(n: tup.n, typ: c.types.autoType)
+    semExpr c, index
+    it.n = index.n
+    wantParRi c, it.n
+    return
   var idx = tup.n
   let idxStart = c.dest.len
   semConstIntExpr c, idx

tests/nimony/sysbasics/tdefault.nif

@@ -1,12 +1,12 @@
 (.nif24)
 ,1,tests/nimony/sysbasics/tdefault.nim(stmts
- (discard 58,706,lib/std/system.nim
+ (discard 58,712,lib/std/system.nim
   (expr "")) ,1
- (discard 52,681,lib/std/system.nim
+ (discard 52,687,lib/std/system.nim
   (expr +0)) ,3
- (discard 56,709,lib/std/system.nim
+ (discard 56,715,lib/std/system.nim
   (expr 1
-   (conv ~41,~709,tests/nimony/sysbasics/tdefault.nim
+   (conv ~41,~715,tests/nimony/sysbasics/tdefault.nim
     (ptr ~12,3,lib/std/system.nim
      (i -1)) 1
     (nil)))) 10,4
@@ -40,7 +40,7 @@
      (stmts
       (ret "c"))))
    (ret result.0))) ,5
- (discard 57,703,lib/std/system.nim
+ (discard 57,709,lib/std/system.nim
   (expr 3 a.0.tde837gue)) 9,7
  (type ~4 :Obj.0.tde837gue . . . 2
   (object . ~9,1
@@ -55,14 +55,14 @@
      (fld :b.1.tde837gue . . 3 Enum.0.tde837gue .)) .))) ,12
  (discard 15
   (obj 1 Obj.0.tde837gue
-   (kv x.0.tde837gue 37,670,lib/std/system.nim
+   (kv x.0.tde837gue 37,676,lib/std/system.nim
     (expr +0))
-   (kv y.0.tde837gue 43,694,lib/std/system.nim
+   (kv y.0.tde837gue 43,700,lib/std/system.nim
     (expr ""))
    (kv z.0.tde837gue
-    (tup 39,666,lib/std/system.nim
-     (expr ~33,~308
-      (false)) 42,696,lib/std/system.nim
+    (tup 39,672,lib/std/system.nim
+     (expr ~33,~311
+      (false)) 42,702,lib/std/system.nim
      (expr 3 a.0.tde837gue))))) ,14
  (proc 5 :foo.0.tde837gue . . . 8
   (params 1
@@ -76,14 +76,14 @@
     (i -1) .) 4
    (var :data.0 . . 10,~3 Obj.0.tde837gue 10
     (obj ,~3 Obj.0.tde837gue
-     (kv x.0.tde837gue 36,667,lib/std/system.nim
+     (kv x.0.tde837gue 36,673,lib/std/system.nim
       (expr +0))
-     (kv y.0.tde837gue 42,691,lib/std/system.nim
+     (kv y.0.tde837gue 42,697,lib/std/system.nim
       (expr ""))
      (kv z.0.tde837gue
-      (tup 38,663,lib/std/system.nim
-       (expr ~33,~308
-        (false)) 41,693,lib/std/system.nim
+      (tup 38,669,lib/std/system.nim
+       (expr ~33,~311
+        (false)) 41,699,lib/std/system.nim
        (expr 3 a.0.tde837gue))))) 4,1
    (var :x.2 . .
     (string) 4 "abc") 7,2
@@ -107,7 +107,7 @@
  (asgn ~7 global.0.tde837gue 10
   (obj ~5,~5 MyObject.0.tde837gue 2
    (kv ~2 x.1.tde837gue 2 +123)
-   (kv y.1.tde837gue 35,654,lib/std/system.nim
+   (kv y.1.tde837gue 35,660,lib/std/system.nim
     (expr +0)))) 7,29
  (asgn ~7 global.0.tde837gue 10
   (obj ~5,~6 MyObject.0.tde837gue 2
@@ -119,7 +119,7 @@
    (asgn ~7 global.0.tde837gue 10
     (obj ~7,~8 MyObject.0.tde837gue 2
      (kv ~2 x.1.tde837gue 2 +123)
-     (kv y.1.tde837gue 33,651,lib/std/system.nim
+     (kv y.1.tde837gue 33,657,lib/std/system.nim
       (expr +0)))) 7,1
    (asgn ~7 global.0.tde837gue 10
     (obj ~7,~9 MyObject.0.tde837gue 2
@@ -129,7 +129,7 @@
   (asgn ~7 global.0.tde837gue 10
    (obj ~7,~8 MyObject.0.tde837gue 2
     (kv ~2 x.1.tde837gue 2 +123)
-    (kv y.1.tde837gue 33,651,lib/std/system.nim
+    (kv y.1.tde837gue 33,657,lib/std/system.nim
      (expr +0)))) 7,1
   (asgn ~7 global.0.tde837gue 10
    (obj ~7,~9 MyObject.0.tde837gue 2
@@ -174,7 +174,7 @@
    (result :result.3 . . 9,~1 GenericObj.1.tde837gue .) 7
    (asgn ~7 result.3 15
     (obj ~1,~4 GenericObj.1.tde837gue
-     (kv x.3.tde837gue 28,640,lib/std/system.nim
+     (kv x.3.tde837gue 28,646,lib/std/system.nim
       (expr +0)))) 9,1
    (asgn ~3
     (dot ~6 result.3 x.3.tde837gue +0) 2 x.4) ~2,~1

tests/nimony/sysbasics/tindex.nim

@@ -12,3 +12,14 @@ proc main() =
   let z = cstr[1]
   let zt: char = z
   cstr[1] = zt
+
+  var tup: tuple[a: int, b: string, c: bool]
+  let t1 = tup[0]
+  let t1t: int = t1
+  tup[0] = t1t
+  let t2 = tup[1]
+  let t2t: string = t2
+  tup[1] = t2t
+  let t3 = tup[2]
+  let t3t: bool = t3
+  tup[2] = t3t