unify tuple expressions (nim-lang#13793)

* unify tuple expressions

* fix test

* fix test

* apply feedback

* Handle empty tuples

* Fix rendering named unary tuple

* Protect static NimNode against stripping

* Slightly less hacky

* Revert "Slightly less hacky"

This reverts commit 170c5ae.

* Slightly less hacky

* Cleanup

* Fix test

* Fix another test

* Add condsym

* Rebase fallout

* changelog: Move from compiler changes to language changes

* Add stricter tests

* Add empty tuple example to doc/astspec

* Fix test

Co-authored-by: Clyybber <darkmine956@gmail.com>

changelog.md

@@ -274,6 +274,9 @@
 
 - Custom numeric literals (e.g. `-128'bignum`) are now supported.
 
+- Tuple expressions are now parsed consistently as
+  `nnkTupleConstr` node. Will affect macros expecting nodes to be of `nnkPar`.
+
 
 ## Compiler changes
 

compiler/condsyms.nim

@@ -131,3 +131,4 @@ proc initDefines*(symbols: StringTableRef) =
   defineSymbol("nimHasHintAsError")
   defineSymbol("nimHasSpellSuggest")
   defineSymbol("nimHasCustomLiterals")
+  defineSymbol("nimHasUnifiedTuple")

compiler/parser.nim

@@ -421,10 +421,9 @@ proc exprColonEqExprListAux(p: var Parser, endTok: TokType, result: PNode) =
     var a = exprColonEqExpr(p)
     result.add(a)
     if p.tok.tokType != tkComma: break
-    getTok(p)
-    # (1,) produces a tuple expression
-    if endTok == tkParRi and p.tok.tokType == tkParRi and result.kind == nkPar:
+    elif result.kind == nkPar:
       result.transitionSonsKind(nkTupleConstr)
+    getTok(p)
     skipComment(p, a)
   optPar(p)
   eat(p, endTok)
@@ -584,7 +583,10 @@ proc parsePar(p: var Parser): PNode =
     semiStmtList(p, result)
   elif p.tok.tokType == tkCurlyDotLe:
     result.add(parseStmtPragma(p))
-  elif p.tok.tokType != tkParRi:
+  elif p.tok.tokType == tkParRi:
+    # Empty tuple '()'
+    result.transitionSonsKind(nkTupleConstr)
+  else:
     var a = simpleExpr(p)
     if p.tok.tokType == tkDo:
       result = postExprBlocks(p, a)
@@ -605,13 +607,14 @@ proc parsePar(p: var Parser): PNode =
       semiStmtList(p, result)
     else:
       a = colonOrEquals(p, a)
+      if a.kind == nkExprColonExpr:
+        result.transitionSonsKind(nkTupleConstr)
       result.add(a)
       if p.tok.tokType == tkComma:
         getTok(p)
         skipComment(p, a)
         # (1,) produces a tuple expression:
-        if p.tok.tokType == tkParRi:
-          result.transitionSonsKind(nkTupleConstr)
+        result.transitionSonsKind(nkTupleConstr)
         # progress guaranteed
         while p.tok.tokType != tkParRi and p.tok.tokType != tkEof:
           var a = exprColonEqExpr(p)

compiler/renderer.nim

@@ -1182,7 +1182,7 @@ proc gsub(g: var TSrcGen, n: PNode, c: TContext) =
   of nkTupleConstr:
     put(g, tkParLe, "(")
     gcomma(g, n, c)
-    if n.len == 1: put(g, tkComma, ",")
+    if n.len == 1 and n[0].kind != nkExprColonExpr: put(g, tkComma, ",")
     put(g, tkParRi, ")")
   of nkCurly:
     put(g, tkCurlyLe, "{")

compiler/vm.nim

@@ -2228,6 +2228,12 @@ proc prepareVMValue(arg: PNode): PNode =
   if arg.kind in nkLiterals:
     return arg
 
+  if arg.kind == nkExprColonExpr and arg[0].typ != nil and
+     arg[0].typ.sym != nil and arg[0].typ.sym.magic == mPNimrodNode:
+    # Poor mans way of protecting static NimNodes
+    # XXX: Maybe we need a nkNimNode?
+    return arg
+
   result = copyNode(arg)
   if arg.kind == nkTupleConstr:
     for child in arg:

doc/astspec.txt

@@ -329,19 +329,56 @@ AST:
 Parentheses
 -----------
 
-Parentheses for affecting operator precedence or tuple construction
-are built with the ``nnkPar`` node.
+Parentheses for affecting operator precedence use the ``nnkPar`` node.
 
 Concrete syntax:
 
 .. code-block:: nim
-  (1, 2, (3))
+  (a + b) * c
 
 AST:
 
 .. code-block:: nim
-  nnkPar(nnkIntLit(1), nnkIntLit(2), nnkPar(nnkIntLit(3)))
+  nnkInfix(nnkIdent("*"),
+    nnkPar(
+      nnkInfix(nnkIdent("+"), nnkIdent("a"), nnkIdent("b"))),
+    nnkIdent("c"))
 
+Tuple Constructors
+------------------
+
+Nodes for tuple construction are built with the ``nnkTupleConstr`` node.
+
+Concrete syntax:
+
+.. code-block:: nim
+  (1, 2, 3)
+  (a: 1, b: 2, c: 3)
+  ()
+
+AST:
+
+.. code-block:: nim
+  nnkTupleConstr(nnkIntLit(1), nnkIntLit(2), nnkIntLit(3))
+  nnkTupleConstr(
+    nnkExprColonExpr(nnkIdent("a"), nnkIntLit(1)),
+    nnkExprColonExpr(nnkIdent("b"), nnkIntLit(2)),
+    nnkExprColonExpr(nnkIdent("c"), nnkIntLit(3)))
+
+Since the one tuple would be syntactically identical to parentheses
+with an expression in them, the parser expects a trailing comma for
+them. For tuple constructors with field names, this is not necessary.
+
+.. code-block:: nim
+  (1,)
+  (a: 1)
+
+AST:
+
+.. code-block:: nim
+  nnkTupleConstr(nnkIntLit(1))
+  nnkTupleConstr(
+    nnkExprColonExpr(nnkIdent("a"), nnkIntLit(1)))
 
 Curly braces
 ------------

tests/ast_pattern_matching.nim

@@ -133,8 +133,8 @@ proc matchLengthKind*(arg: NimNode; kind: NimNodeKind; length: int): MatchingErr
   matchLengthKind(arg, {kind}, length)
 
 proc matchValue(arg: NimNode; kind: set[NimNodeKind]; value: SomeInteger): MatchingError {.compileTime.} =
-  let kindFail   = not(kind.card == 0 or arg.kind in kind)
-  let valueFail  = arg.intVal != int(value)
+  template kindFail: bool  = not(kind.card == 0 or arg.kind in kind)
+  template valueFail: bool = arg.intVal != int(value)
   if kindFail or valueFail:
     result.node = arg
     result.kind = WrongKindValue

tests/astspec/tastspec.nim

@@ -327,19 +327,43 @@ static:
 
   testArrayAccessOperator(x[y])
 
-
-
   ## Parentheses
 
   scope:
-
     let ast = myquote:
-      (1, 2, (3))
+      (a + b) * c
 
     ast.matchAst:
-    of nnkPar(nnkIntLit(intVal = 1), nnkIntLit(intVal = 2), nnkPar(nnkIntLit(intVal = 3))):
-      echo "ok"
+    of nnkInfix(ident"*", nnkPar(nnkInfix(ident"+", ident"a", ident"b")), ident"c"):
+      echo "parentheses ok"
 
+  ## Tuple Constructors
+
+  scope:
+    let ast = myquote:
+      (1, 2, 3)
+      (a: 1, b: 2, c: 3)
+      (1,)
+      (a: 1)
+      ()
+
+    for it in ast:
+      echo it.lispRepr
+      it.matchAst:
+      of nnkTupleConstr(nnkIntLit(intVal = 1), nnkIntLit(intVal = 2), nnkIntLit(intVal = 3)):
+        echo "simple tuple ok"
+      of nnkTupleConstr(
+        nnkExprColonExpr(ident"a", nnkIntLit(intVal = 1)),
+        nnkExprColonExpr(ident"b", nnkIntLit(intVal = 2)),
+        nnkExprColonExpr(ident"c", nnkIntLit(intVal = 3))
+      ):
+        echo "named tuple ok"
+      of nnkTupleConstr(nnkIntLit(intVal = 1)):
+        echo "one tuple ok"
+      of nnkTupleConstr(nnkExprColonExpr(ident"a", nnkIntLit(intVal = 1))):
+        echo "named one tuple ok"
+      of nnkTupleConstr():
+       echo "empty tuple ok"
 
   ## Curly braces
 

tests/compiler/tprefixmatches.nim

@@ -5,7 +5,7 @@ macro check(val, body: untyped): untyped =
   result = newStmtList()
   expectKind body, nnkStmtList
   for b in body:
-    expectKind b, nnkPar
+    expectKind b, nnkTupleConstr
     expectLen b, 2
     let p = b[0]
     let s = b[1]

tests/lexer/tunary_minus.nim

@@ -45,7 +45,7 @@ template main =
     doAssert lispReprStr([-1]) == """(Bracket (IntLit -1))"""
     doAssert (-1, 2)[0] == minusOne:
       "unable to handle negatives after parenthesis"
-    doAssert lispReprStr((-1, 2)) == """(Par (IntLit -1) (IntLit 2))"""
+    doAssert lispReprStr((-1, 2)) == """(TupleConstr (IntLit -1) (IntLit 2))"""
     proc x(): int =
       var a = 1;-1  # the -1 should act as the return value
     doAssert x() == minusOne:

tests/macros/tdumpast.nim

@@ -48,3 +48,34 @@ macro fun3(): untyped =
     int | float | array | seq | object | ptr | pointer | float32
   doAssert n.repr == "int | float | array | seq | object | ptr | pointer | float32", n.repr
 fun3()
+
+macro fun4() =
+  let n = quote do:
+    (a: 1)
+  doAssert n.repr == "(a: 1)", n.repr
+fun4()
+
+# nkTupleConstr vs nkPar tests:
+block: # lispRepr
+  macro lispRepr2(a: untyped): string = newLit a.lispRepr
+
+  doAssert lispRepr2(()) == """(TupleConstr)"""
+  doAssert lispRepr2((a: 1)) == """(TupleConstr (ExprColonExpr (Ident "a") (IntLit 1)))"""
+  doAssert lispRepr2((a: 1, b: 2)) == """(TupleConstr (ExprColonExpr (Ident "a") (IntLit 1)) (ExprColonExpr (Ident "b") (IntLit 2)))"""
+  doAssert lispRepr2((1,)) == """(TupleConstr (IntLit 1))"""
+  doAssert lispRepr2((1, 2)) == """(TupleConstr (IntLit 1) (IntLit 2))"""
+  doAssert lispRepr2((1, 2, 3.0)) == """(TupleConstr (IntLit 1) (IntLit 2) (FloatLit 3.0))"""
+  doAssert lispRepr2((1)) == """(Par (IntLit 1))"""
+  doAssert lispRepr2((1+2)) == """(Par (Infix (Ident "+") (IntLit 1) (IntLit 2)))"""
+
+block: # repr
+  macro repr2(a: untyped): string = newLit a.repr
+
+  doAssert repr2(()) == "()"
+  doAssert repr2((a: 1)) == "(a: 1)"
+  doAssert repr2((a: 1, b: 2)) == "(a: 1, b: 2)"
+  doAssert repr2((1,)) == "(1,)"
+  doAssert repr2((1, 2)) == "(1, 2)"
+  doAssert repr2((1, 2, 3.0)) == "(1, 2, 3.0)"
+  doAssert repr2((1)) == "(1)"
+  doAssert repr2((1+2)) == "(1 + 2)"

tests/parser/tpostexprblocks.nim

@@ -464,7 +464,7 @@ StmtList
           DiscardStmt
             Empty
       OfBranch
-        Par
+        TupleConstr
           Ident "a"
           Ident "b"
         StmtList
@@ -476,7 +476,7 @@ StmtList
           DiscardStmt
             Empty
       ElifBranch
-        Par
+        TupleConstr
           Ident "a"
           Ident "b"
         StmtList
@@ -488,7 +488,7 @@ StmtList
           DiscardStmt
             Empty
       ExceptBranch
-        Par
+        TupleConstr
           Ident "a"
           Ident "b"
         StmtList

tests/parser/ttypemodifiers.nim

@@ -21,7 +21,7 @@ StmtList
       Ident "PtrTuple"
       Empty
       PtrTy
-        Par
+        TupleConstr
           Ident "int"
           Ident "string"
     TypeDef
@@ -43,14 +43,14 @@ StmtList
       Ident "RefTupleType"
       Empty
       RefTy
-        Par
+        TupleConstr
           Ident "int"
           Ident "string"
     TypeDef
       Ident "RefTupleVars"
       Empty
       RefTy
-        Par
+        TupleConstr
           Ident "a"
           Ident "b"
     TypeDef
@@ -80,7 +80,7 @@ StmtList
       Empty
       Command
         Ident "static"
-        Par
+        TupleConstr
           Ident "int"
           Ident "string"
     TypeDef
@@ -155,15 +155,15 @@ StmtList
       Empty
       Command
         Ident "type"
-        Par
+        TupleConstr
           Ident "a"
           Ident "b"
     TypeDef
       Ident "TypeTuple"
       Empty
       Command
         Ident "type"
-        Par
+        TupleConstr
           Ident "int"
           Ident "string"
     TypeDef
@@ -287,7 +287,7 @@ StmtList
       IdentDefs
         Ident "refTuple2"
         RefTy
-          Par
+          TupleConstr
             Ident "int"
             Ident "string"
         Empty
@@ -524,4 +524,3 @@ dumpTree:
     static:
       staticStmtList1
       staticStmtList2
-