Implement support for optionally specifying the 'var' keyword in 'for' loops

diff --git a/doc/17-language-reference.md b/doc/17-language-reference.md
index d2a8658117cef702c192c53987048476ea9d2719..9bd31d6b791d22f9057e19a3524882bea4965cb4 100644 (file)
--- a/doc/17-language-reference.md
+++ b/doc/17-language-reference.md
@@ -830,7 +830,7 @@ Example:
 
     var list = [ "a", "b", "c" ]
 
-    for (item in list) {
+    for (var item in list) {
       log("Item: " + item)
     }
 
@@ -841,7 +841,7 @@ Iterating over dictionaries can be accomplished in a similar manner:
 
     var dict = { a = 3, b = 7 }
 
-    for (key => value in dict) {
+    for (var key => var value in dict) {
       log("Key: " + key + ", Value: " + value)
     }
 
@@ -849,6 +849,9 @@ The `continue` and `break` keywords can be used to control how the loop is execu
 skips over the remaining expressions for the loop body and begins the next loop evaluation. The `break` keyword
 breaks out of the loop.
 
+The `var` keyword is optional when declaring variables in the loop's header. Variables declared without the `var`
+keyword are nonetheless local to the function.
+
 ## Constructors <a id="constructor"></a>
 
 In order to create a new value of a specific type constructor calls may be used.

diff --git a/lib/config/config_parser.yy b/lib/config/config_parser.yy
index 70f309bd3f7d0a8338329d151b4e2e1671206999..1a47c69328af216abfc1d06627c209f3f387ef1d 100644 (file)
--- a/lib/config/config_parser.yy
+++ b/lib/config/config_parser.yy
@@ -469,6 +469,10 @@ combined_set_op: T_SET
        | T_SET_BINARY_OR
        ;
 
+optional_var: /* empty */
+       | T_VAR
+       ;
+
 lterm: T_LIBRARY rterm
        {
                $$ = new LibraryExpression(std::unique_ptr<Expression>($2), @$);
@@ -603,7 +607,7 @@ lterm: T_LIBRARY rterm
        }
        | apply
        | object
-       | T_FOR '(' identifier T_FOLLOWS identifier T_IN rterm ')'
+       | T_FOR '(' optional_var identifier T_FOLLOWS optional_var identifier T_IN rterm ')'
        {
                BeginFlowControlBlock(context, FlowControlContinue | FlowControlBreak, true);
        }
@@ -611,11 +615,11 @@ lterm: T_LIBRARY rterm
        {
                EndFlowControlBlock(context);
 
-               $$ = new ForExpression(*$3, *$5, std::unique_ptr<Expression>($7), std::unique_ptr<Expression>($10), @$);
-               delete $3;
-               delete $5;
+               $$ = new ForExpression(*$4, *$7, std::unique_ptr<Expression>($9), std::unique_ptr<Expression>($12), @$);
+               delete $4;
+               delete $7;
        }
-       | T_FOR '(' identifier T_IN rterm ')'
+       | T_FOR '(' optional_var identifier T_IN rterm ')'
        {
                BeginFlowControlBlock(context, FlowControlContinue | FlowControlBreak, true);
        }
@@ -623,8 +627,8 @@ lterm: T_LIBRARY rterm
        {
                EndFlowControlBlock(context);
 
-               $$ = new ForExpression(*$3, "", std::unique_ptr<Expression>($5), std::unique_ptr<Expression>($8), @$);
-               delete $3;
+               $$ = new ForExpression(*$4, "", std::unique_ptr<Expression>($6), std::unique_ptr<Expression>($9), @$);
+               delete $4;
        }
        | T_FUNCTION identifier '(' identifier_items ')' use_specifier
        {
@@ -1103,24 +1107,24 @@ use_specifier_item: identifier
        ;
 
 apply_for_specifier: /* empty */
-       | T_FOR '(' identifier T_FOLLOWS identifier T_IN rterm ')'
+       | T_FOR '(' optional_var identifier T_FOLLOWS optional_var identifier T_IN rterm ')'
        {
-               context->m_FKVar.top() = *$3;
-               delete $3;
+               context->m_FKVar.top() = *$4;
+               delete $4;
 
-               context->m_FVVar.top() = *$5;
-               delete $5;
+               context->m_FVVar.top() = *$7;
+               delete $7;
 
-               context->m_FTerm.top() = $7;
+               context->m_FTerm.top() = $9;
        }
-       | T_FOR '(' identifier T_IN rterm ')'
+       | T_FOR '(' optional_var identifier T_IN rterm ')'
        {
-               context->m_FKVar.top() = *$3;
-               delete $3;
+               context->m_FKVar.top() = *$4;
+               delete $4;
 
                context->m_FVVar.top() = "";
 
-               context->m_FTerm.top() = $5;
+               context->m_FTerm.top() = $6;
        }
        ;