Changeset 1591 for cobra/trunk/Source/Expr.cobra

Timestamp:

08/28/08 04:00:40 (4 months ago)

Author:

Chuck.Esterbrook

Message:

Added support for "extended initializers" which allow you to set properties of the object in the same call being used to create the object.

Files:

• cobra/trunk/Source/Expr.cobra (modified) (6 diffs)

cobra/trunk/Source/Expr.cobra

@@ -1353 +1353 @@
         var _expr as Expr
         var _args as List<of Expr>
+        var _hasKeywordArg as bool  # such as Foo(1, a=2)
+        var _isForAttribute as bool  # see Attributes.cobra
+        var _helperMethod as Method?
 
         def init(token as IToken, expr as Expr, args as List<of Expr>)
@@ -1364 +1367 @@
                 .addField('expr', _expr)
                 .addField('args', _args)
+                .addField('hasKeywordArg', .hasKeywordArg)
+                .addField('isForAttribute', .isForAttribute)
 
         get expr from var
@@ -1369 +1374 @@
         get args from var
                 has Subnodes
+
+        get hasKeywordArg from var
+
+        pro isForAttribute from var
 
         get hasError as bool is override
@@ -1412 +1421 @@
                                 return                                  
 
-                for arg in _args
+                for arg in .args
                         try
                                 if arg inherits AssignExpr
+                                        _hasKeywordArg = true # uu
+                                        # TODO: check that left side is an IdentfierExpr
+                                        # TODO: check property name
                                         arg.right.bindImp  # 'x=y' has special treatment in arguments
                                 else
+                                        if _hasKeywordArg
+                                                .throwError('Cannot have a non-keyword argument ("[arg.toCobraSource]") after a keyword argument. All positional arguments must come before all keyword arguments.')
                                         arg.bindImp
                         catch ne as NodeException
@@ -1448 +1462 @@
                                 assert false, expr
 
+                if .hasKeywordArg and not .isForAttribute  # uu
+                        _makeHelperMethod
+                        
+        def _makeHelperMethod
+                """
+                Add a private helper method to the current box to support extended initializer.
+
+                Foo(expr0, expr1, bar=expr2) -->
+                        call:
+                                _ch_ext_init_1207(expr0, expr1, expr2)
+                        def:
+                                def _ch_ext_init_1207(arg0 as int, arg1 as int, /#bar=#/arg2 as int)
+                                        obj = Foo(arg0, arg1)
+                                        obj.bar = arg2
+                                        return obj
+                """
+                box = .compiler.curBox
+                paramsForDecl = List<of Param>()
+                argsForInitCall = List<of Expr>()  # args to pass to `Foo(arg0, arg1)`
+                propsToSet = List<of AssignExpr>()  # props to set as `obj.bar = arg2` etc.
+                firstPropArg = -1
+                i = 0
+                for arg in .args
+                        if arg inherits AssignExpr
+                                propsToSet.add(arg)
+                                if firstPropArg == -1, firstPropArg = i
+                                arg = arg.right
+                        else
+                                argsForInitCall.add(arg)
+                        paramsForDecl.add(Param(box.token.copy('ID', 'arg[i]'), arg.type))
+                        i += 1
+                name = '_ch_ext_init_[.serialNum]'  # ch = class helper, ext = extended, init = initializer
+                token = box.token.copy
+                m = Method(token.copy('ID', name), box, name, paramsForDecl, _type, nil, ['shared'], AttributeList(), '')
+                m.locals.add(LocalVar(token.copy('ID', 'obj'), .type))
+
+                objId = IdentifierExpr(token.copy('ID', 'obj'), 'obj')
+                callExpr = PostCallExpr(token.copy('ID', .type.name), IdentifierExpr(token.copy('ID', .type.name), .type), argsForInitCall)
+                assign = AssignExpr(token.copy('ASSIGN', '='), 'ASSIGN', objId, callExpr)
+                m.addStmt(assign)
+
+                i = firstPropArg
+                for propSetExpr in propsToSet
+                        propName = (propSetExpr.left to IdentifierExpr).name
+                        memberExpr = DotExpr(token.copy('DOT', '.'), 'DOT', IdentifierExpr(token.copy('ID', 'obj')), MemberExpr(token.copy('ID', propName)))
+                        assign = AssignExpr(token.copy('ASSIGN', '='), 'ASSIGN', memberExpr, IdentifierExpr(token.copy('ID', 'arg[i]')))
+                        m.addStmt(assign)
+                        i += 1
+
+                retStmt = ReturnStmt(token.copy('RETURN', 'return'), IdentifierExpr(token.copy('ID', 'obj'), 'obj'))
+                m.addStmt(retStmt)
+
+                m.bindAll
+                box.addDecl(m)
+                _helperMethod = m
+
         def toCobraSource as String is override
                 sb = StringBuilder()
@@ -1453 +1523 @@
                 sb.append('(')
                 sep = ''
-                for arg in _args
+                for arg in .args
                         sb.append(sep)
                         sb.append(arg.toCobraSource)