Script|libdeng2: Creating records with expressions

Previously it was only possible to create a new record using the
“record” statement or the Record() function. This commit makes it
possible to put “record” in front of any expression that refers to
an identifier, and that identifier will be created as a (sub)record.

For instance:

<pre># Old way:
record a
a.b = 1
record a.sub
# Alternatively: a.sub = Record()
a.sub.c = 2

# New way:
(record a).b = 1
a.(record sub).c = 2</pre>

doomsday/libdeng2/src/scriptsys/nameexpression.cpp

@@ -46,7 +46,7 @@ Value *NameExpression::evaluate(Evaluator &evaluator) const
 {
     //LOG_AS("NameExpression::evaluate");
     //std::cout << "NameExpression::evaluator: " << _flags.to_string() << "\n";
-    //LOG_DEBUG("path = %s, scope = %x") << _path << evaluator.names();
+    LOGDEV_SCR_XVERBOSE_DEBUGONLY("evaluating name:\"%s\" flags:%x", _identifier << flags());
 
     // Collect the namespaces to search.
     Evaluator::Namespaces spaces;

doomsday/libdeng2/src/scriptsys/parser.cpp

@@ -619,7 +619,7 @@ Expression *Parser::parseExpression(TokenRange const &fullRange, Expression::Fla
     TokenRange range = fullRange;
 
     LOG_AS("parseExpression");
-    LOGDEV_SCR_XVERBOSE_DEBUGONLY("", range.asText());
+    LOGDEV_SCR_XVERBOSE_DEBUGONLY("%s (flags:%x)", range.asText() << flags);
 
     if(!range.size())
     {
@@ -633,6 +633,21 @@ Expression *Parser::parseExpression(TokenRange const &fullRange, Expression::Fla
         range = range.shrink(1);
     }
 
+    // Do we have a record declaration in the expression?
+    if(range.firstToken().type() == Token::KEYWORD &&
+       range.firstToken().equals(ScriptLex::RECORD))
+    {
+        LOGDEV_SCR_XVERBOSE_DEBUGONLY("declaration expression: RECORD %s", range.startingFrom(1).asText());
+
+        if(range.size() == 1)
+        {
+            throw MissingTokenError("Parser::parseDeclarationExpression",
+                                    "Expected identifier to follow " + range.firstToken().asText());
+        }
+        return parseExpression(range.startingFrom(1),
+                               flags | Expression::LocalOnly | Expression::NewSubrecord);
+    }
+
     TokenRange leftSide = range.between(0, 0);
     TokenRange rightSide = leftSide;
 
@@ -673,7 +688,7 @@ ArrayExpression *Parser::parseArrayExpression(TokenRange const &range)
             "Expected brackets for the array expression beginning at " + 
             range.firstToken().asText());
     }    
-    return parseList(range.between(1, range.size() - 1));
+    return parseList(range.shrink(1));
 }
 
 DictionaryExpression *Parser::parseDictionaryExpression(TokenRange const &range)
@@ -791,7 +806,16 @@ OperatorExpression *Parser::parseOperatorExpression(Operator op, TokenRange cons
                                              Expression::ByReference : Expression::ByValue);
 
         Expression::Flags rightOpFlags = rightFlags;
-        if(op != MEMBER) rightOpFlags &= ~Expression::ByReference;
+        if(op == MEMBER)
+        {
+            // Don't create new variables for the left side of the member. The only place
+            // where a new variable is created is on the right.
+            leftOpFlags &= ~Expression::NewVariable;
+        }
+        else
+        {
+            rightOpFlags &= ~Expression::ByReference;
+        }
 
         // Binary operation.
         QScopedPointer<Expression> leftOperand(parseExpression(leftSide, leftOpFlags));

doomsday/tests/test_script/kitchen_sink.de

@@ -449,14 +449,21 @@ end
 # ---------------------------------------------------------------------------
 sections.begin('RECORDS')
 
-sections.subsection('Creating a record.')
+sections.subsection('Creating a record with a statement.')
 record myrec
 print len(myrec)
 print "Alternative way using Record()."
 del myrec
 myrec = Record()
 print len(myrec)
 
+sections.subsection('Creating a record using an expression.')
+del myrec
+(record myrec).expressionCreated = True
+myrec.(record subexp).alsoExpCreated = True
+print myrec
+del myrec.subexp
+
 sections.subsection('Creating variables into a record.')
 myrec.newMember = 100
 print len(myrec)