Allow full commands and blocks in type sections (nim-lang#19181)

* allow full commands and blocks in type sections
* update grammar
* fix changelog [skip ci]
* more tests
* even more tests

changelog.md

@@ -61,6 +61,9 @@
   ```
 - [Case statement macros](manual.html#macros-case-statement-macros) are no longer experimental,
   meaning you no longer need to enable the experimental switch `caseStmtMacros` to use them.
+- Full command syntax and block arguments i.e. `foo a, b: c` are now allowed
+  for the right-hand side of type definitions in type sections. Previously
+  they would error with "invalid indentation".
 
 ## Compiler changes
 

compiler/parser.nim

@@ -811,7 +811,7 @@ proc primarySuffix(p: var Parser, r: PNode,
   #|       | DOTLIKEOP optInd symbol generalizedLit?
   #|       | '[' optInd exprColonEqExprList optPar ']'
   #|       | '{' optInd exprColonEqExprList optPar '}'
-  #|       | &( '`'|IDENT|literal|'cast'|'addr'|'type') expr # command syntax
+  #|       | &( '`'|IDENT|literal|'cast'|'addr'|'type') expr (comma expr)* # command syntax
   result = r
 
   # progress guaranteed
@@ -821,14 +821,14 @@ proc primarySuffix(p: var Parser, r: PNode,
     of tkParLe:
       # progress guaranteed
       if p.tok.strongSpaceA > 0:
-        # inside type sections, expressions such as `ref (int, bar)`
-        # are parsed as a nkCommand with a single tuple argument (nkPar)
+        result = commandExpr(p, result, mode)
+        # type sections allow full command syntax
         if mode == pmTypeDef:
-          result = newNodeP(nkCommand, p)
-          result.add r
-          result.add primary(p, pmNormal)
-        else:
-          result = commandExpr(p, result, mode)
+          var isFirstParam = false
+          while p.tok.tokType == tkComma:
+            getTok(p)
+            optInd(p, result)
+            result.add(commandParam(p, isFirstParam, mode))
         break
       result = namedParams(p, result, nkCall, tkParRi)
       if result.len > 1 and result[1].kind == nkExprColonExpr:
@@ -869,9 +869,18 @@ proc primarySuffix(p: var Parser, r: PNode,
           # actually parsing {.push hints:off.} as {.push(hints:off).} is a sweet
           # solution, but pragmas.nim can't handle that
           result = commandExpr(p, result, mode)
+          if mode == pmTypeDef:
+            var isFirstParam = false
+            while p.tok.tokType == tkComma:
+              getTok(p)
+              optInd(p, result)
+              result.add(commandParam(p, isFirstParam, mode))
         break
     else:
       break
+  # type sections allow post-expr blocks
+  if mode == pmTypeDef:
+    result = postExprBlocks(p, result)
 
 proc parseOperators(p: var Parser, headNode: PNode,
                     limit: int, mode: PrimaryMode): PNode =
@@ -1342,7 +1351,8 @@ proc parseTypeDesc(p: var Parser): PNode =
   result = binaryNot(p, result)
 
 proc parseTypeDefAux(p: var Parser): PNode =
-  #| typeDefAux = simpleExpr ('not' expr)?
+  #| typeDefAux = simpleExpr ('not' expr
+  #|                         | postExprBlocks)?
   result = simpleExpr(p, pmTypeDef)
   result = binaryNot(p, result)
 

doc/grammar.txt

@@ -60,7 +60,7 @@ primarySuffix = '(' (exprColonEqExpr comma?)* ')'
       | DOTLIKEOP optInd symbol generalizedLit?
       | '[' optInd exprColonEqExprList optPar ']'
       | '{' optInd exprColonEqExprList optPar '}'
-      | &( '`'|IDENT|literal|'cast'|'addr'|'type') expr # command syntax
+      | &( '`'|IDENT|literal|'cast'|'addr'|'type') expr (comma expr)* # command syntax
 pragma = '{.' optInd (exprColonEqExpr comma?)* optPar ('.}' | '}')
 identVis = symbol OPR?  # postfix position
 identVisDot = symbol '.' optInd symbol OPR?
@@ -93,7 +93,8 @@ primary = operatorB primary primarySuffix* |
           ('var' | 'out' | 'ref' | 'ptr' | 'distinct') primary
         /  prefixOperator* identOrLiteral primarySuffix*
 typeDesc = simpleExpr ('not' expr)?
-typeDefAux = simpleExpr ('not' expr)?
+typeDefAux = simpleExpr ('not' expr
+                        | postExprBlocks)?
 postExprBlocks = ':' stmt? ( IND{=} doBlock
                            | IND{=} 'of' exprList ':' stmt
                            | IND{=} 'elif' expr ':' stmt

tests/parser/ttypecommandcomma.nim

@@ -0,0 +1,9 @@
+discard """
+  errormsg: "invalid indentation"
+  line: 8
+  column: 19
+"""
+
+type
+  Foo = call(1, 2), 3:
+    4

tests/parser/ttypecommandindent1.nim

@@ -0,0 +1,9 @@
+discard """
+  errormsg: "invalid indentation"
+  line: 9
+  column: 3
+"""
+
+type
+  Foo = call x, y, z:
+  abc

tests/parser/ttypecommandindent2.nim

@@ -0,0 +1,11 @@
+discard """
+  errormsg: "invalid indentation"
+  line: 10
+  column: 5
+"""
+
+type
+  Foo = call x, y, z:
+      abc
+    do:
+        def

tests/parser/ttypecommandindent3.nim

@@ -0,0 +1,11 @@
+discard """
+  errormsg: "expression expected, but found 'keyword do'"
+  line: 10
+  column: 1
+"""
+
+type
+  Foo = call x, y, z:
+    abc
+do:
+    def