cleaned up command expressions

compiler/parser.nim

@@ -642,8 +642,7 @@ proc primarySuffix(p: var TParser, r: PNode): PNode =
   #|               | '.' optInd ('type' | 'addr' | symbol) generalizedLit?
   #|               | '[' optInd indexExprList optPar ']'
   #|               | '{' optInd indexExprList optPar '}'
-  #|               | &( '`'|IDENT|literal|'cast') expr ^+ ',' # command syntax
-  #|                      (doBlock | macroColon)?
+  #|               | &( '`'|IDENT|literal|'cast') expr # command syntax
   result = r
   while p.tok.indent < 0:
     case p.tok.tokType
@@ -680,10 +679,10 @@ proc primarySuffix(p: var TParser, r: PNode): PNode =
             if p.tok.tokType != tkComma: break
             getTok(p)
             optInd(p, a)
-        if p.tok.tokType == tkDo:
-          parseDoBlocks(p, result)
-        else:
-          result = parseMacroColon(p, result)
+          if p.tok.tokType == tkDo:
+            parseDoBlocks(p, result)
+          else:
+            result = parseMacroColon(p, result)
       break
     else:
       break

doc/grammar.txt

@@ -59,8 +59,7 @@ primarySuffix = '(' (exprColonEqExpr comma?)* ')' doBlocks?
               | '.' optInd ('type' | 'addr' | symbol) generalizedLit?
               | '[' optInd indexExprList optPar ']'
               | '{' optInd indexExprList optPar '}'
-              | &( '`'|IDENT|literal|'cast') expr ^+ ',' # command syntax
-                     (doBlock | macroColon)?
+              | &( '`'|IDENT|literal|'cast') expr # command syntax
 condExpr = expr colcom expr optInd
         ('elif' expr colcom expr optInd)*
          'else' colcom expr

doc/manual.txt

@@ -1315,12 +1315,9 @@ Examples:
 
 .. code-block:: nimrod
 
-  type
-    TCallback = proc (x: int) {.cdecl.}
+  proc printItem(x: int) = ...
 
-  proc printItem(x: Int) = ...
-
-  proc forEach(c: TCallback) =
+  proc forEach(c: proc (x: int) {.cdecl.}) =
     ...
 
   forEach(printItem)  # this will NOT work because calling conventions differ
@@ -2459,6 +2456,17 @@ notation. (Thus an operator can have more than two parameters):
 
   assert `*+`(3, 4, 6) == `*`(a, `+`(b, c))
 
+
+Command invocation syntax
+-------------------------
+
+Routines can be invoked without the ``()`` if the call is syntactially
+a statement. This `command invocation syntax`:idx: also works for
+expressions, but then only a single argument may follow. This restriction
+means ``echo f 1, f 2`` is parsed as ``echo(f(1), f(2))`` and not as
+``echo(f(1, f(2)))``.
+
+
 Closures
 --------
 

tests/parser/tcommand_as_expr.nim

@@ -1,12 +1,17 @@
 discard """
-  output: "12"
+  output: '''140
+5-120'''
 """
 
+proc optarg(x:int):int = x
+proc singlearg(x:int):int = 20*x
+echo optarg 1, singlearg 2
+
+
 proc foo(x: int): int = x-1
 proc foo(x, y: int): int = x-y
 
-let x = foo 7.foo,  # comment here
-            foo(1, foo 8)
-#  12 =       6     -     -6
-echo x
+let x = optarg foo 7.foo
+let y = singlearg foo(1, foo 8)
 
+echo x, y