Implement number prefix parsing (/[\+\-]+/)

Fixes #535

extend.cpp

@@ -5,7 +5,6 @@
 #include "backtrace.hpp"
 #include "paths.hpp"
 #include "parser.hpp"
-#include "debugger.hpp"
 #include "node.hpp"
 #include "sass_util.hpp"
 #include "debug.hpp"
@@ -1580,7 +1579,6 @@ namespace Sass {
       // out and aren't operated on.
       Complex_Selector* pNewSelector = pExtComplexSelector->cloneFully(ctx);
       Complex_Selector* pNewInnerMost = new (ctx.mem) Complex_Selector(pSelector->pstate(), Complex_Selector::ANCESTOR_OF, pUnifiedSelector, NULL);
-      // pNewInnerMost->media_block(pSelector->media_block());
       Complex_Selector::Combinator combinator = pNewSelector->clear_innermost();
       pNewSelector->set_innermost(pNewInnerMost, combinator);
 
@@ -1753,11 +1751,9 @@ namespace Sass {
     pComplexSelector->tail()->has_line_feed(pComplexSelector->has_line_feed());
 
     Node complexSelector = complexSelectorToNode(pComplexSelector, ctx);
-// debug_ast(pComplexSelector->parent());
     DEBUG_PRINTLN(EXTEND_COMPLEX, "EXTEND COMPLEX: " << complexSelector)
 
     Node extendedNotExpanded = Node::createCollection();
-    // extendedNotExpanded.media_block = pComplexSelector->media_block();
 
     for (NodeDeque::iterator complexSelIter = complexSelector.collection()->begin(), complexSelIterEnd = complexSelector.collection()->end(); complexSelIter != complexSelIterEnd; ++complexSelIter) {
       Node& sseqOrOp = *complexSelIter;

parser.cpp

@@ -402,7 +402,6 @@ namespace Sass {
       property_segment = new (ctx.mem) String_Quoted(pstate, lexed);
     }
     Propset* propset = new (ctx.mem) Propset(pstate, property_segment);
-    // debug_ast(property_segment);
     lex< exactly<':'> >();
 
     if (!peek< exactly<'{'> >()) error("expected a '{' after namespaced property", pstate);
@@ -941,6 +940,22 @@ namespace Sass {
     }
   }
 
+  // parse +/- and return false if negative
+  bool Parser::parse_number_prefix()
+  {
+    bool positive = true;
+    while(true) {
+      if (lex < block_comment >()) continue;
+      if (lex < number_prefix >()) continue;
+      if (lex < exactly < '-' > >()) {
+        positive = !positive;
+        continue;
+      }
+      break;
+    }
+    return positive;
+  }
+
   Expression* Parser::parse_map()
   {
     To_String to_string(&ctx);
@@ -1203,17 +1218,18 @@ namespace Sass {
     else if (lex< sequence< not_op, spaces_and_comments > >()) {
       return new (ctx.mem) Unary_Expression(pstate, Unary_Expression::NOT, parse_factor());
     }
+    else if (peek < sequence < one_plus < alternatives < spaces_and_comments, exactly<'-'>, exactly<'+'> > >, number > >()) {
+      if (parse_number_prefix()) return parse_value(); // prefix is positive
+      return new (ctx.mem) Unary_Expression(pstate, Unary_Expression::MINUS, parse_value());
+    }
     else {
       return parse_value();
     }
   }
 
   Expression* Parser::parse_value()
   {
-
-    // ToDo: Move where
     while (lex< block_comment >());
-
     if (lex< uri_prefix >()) {
       Arguments* args = new (ctx.mem) Arguments(pstate);
       Function_Call* result = new (ctx.mem) Function_Call(pstate, "url", args);

parser.hpp

@@ -234,6 +234,7 @@ namespace Sass {
     Simple_Selector* parse_pseudo_selector();
     Attribute_Selector* parse_attribute_selector();
     Block* parse_block();
+    bool parse_number_prefix();
     Declaration* parse_declaration();
     Expression* parse_map_value();
     Expression* parse_map();

prelexer.cpp

@@ -147,6 +147,18 @@ namespace Sass {
       return sequence< exactly<'-'>, exactly<'-'>, identifier >(src);
     }
 
+    // Match number prefix ([\+\-]+)
+    const char* number_prefix(const char* src) {
+      return alternatives <
+        exactly < '+' >,
+        sequence <
+          exactly < '-' >,
+          optional_spaces_and_comments,
+          exactly< '-' >
+        >
+      >(src);
+    }
+
     // Match interpolant schemas
     const char* identifier_schema(const char* src) {
       // follows this pattern: (x*ix*)+ ... well, not quite

prelexer.hpp

@@ -396,6 +396,8 @@ namespace Sass {
     const char* quoted_string(const char* src);
     // Match interpolants.
     const char* interpolant(const char* src);
+    // Match number prefix ([\+\-]+)
+    const char* number_prefix(const char* src);
 
     // Whitespace handling.
     const char* optional_spaces(const char* src);