Need more utility functions.

src/prelexer.cpp

@@ -27,7 +27,7 @@ namespace Sass {
     char* xdigits(char* src) { return one_plus<xdigit>(src); }
     char* alnums(char* src) { return one_plus<alnum>(src); }
     char* puncts(char* src) { return one_plus<punct>(src); }
-    
+        
     // Match a line comment.
     extern const char slash_slash[] = "//";
     char* line_comment(char* src) { return to_endl<slash_slash>(src); }
@@ -37,6 +37,10 @@ namespace Sass {
     char* block_comment(char* src) {
       return delimited_by<slash_star, star_slash, false>(src);
     }
+    // Match either comment.
+    char* comment(char* src) {
+      return alternatives<block_comment, line_comment>(src);
+    }
     // Match double- and single-quoted strings.
     char* double_quoted_string(char* src) {
       return delimited_by<'"', '"', true>(src);
@@ -54,6 +58,13 @@ namespace Sass {
       return delimited_by<hash_lbrace, rbrace, false>(src);
     }
     
+    // Whitespace handling.
+    char* optional_spaces(char* src) { return optional<spaces>(src); }
+    char* optional_comment(char* src) { return optional<comment>(src); }
+    char* spaces_and_comments(char* src) {
+      return zero_plus< alternatives<spaces, comment> >(src);
+    }
+    
     // Match CSS identifiers.
     char* identifier(char* src) {
       return sequence< optional< exactly<'-'> >,
@@ -121,5 +132,19 @@ namespace Sass {
     char* prefix_match(char* src) { return exactly<caret_equal>(src); }
     char* suffix_match(char* src) { return exactly<dollar_equal>(src); }
     char* substring_match(char* src) { return exactly<star_equal>(src); }
+    // Match CSS combinators.
+    char* adjacent_to(char* src) {
+      return sequence< optional_spaces, exactly<'+'> >(src);
+    }
+    char* precedes(char* src) {
+      return sequence< optional_spaces, exactly<'~'> >(src);
+    }
+    char* parent_of(char* src) {
+      return sequence< optional_spaces, exactly<'>'> >(src);
+    }
+    char* ancestor_of(char* src) {
+      return spaces(src);
+    }
+
   }
 }
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src/prelexer.hpp

@@ -201,6 +201,8 @@ namespace Sass {
     char* line_comment(char* src);
     // Match a block comment.
     char* block_comment(char* src);
+    // Match either.
+    char* comment(char* src);
     // Match double- and single-quoted strings.
     char* double_quoted_string(char* src);
     char* single_quoted_string(char* src);
@@ -208,6 +210,11 @@ namespace Sass {
     // Match interpolants.
     char* interpolant(char* src);
 
+    // Whitespace handling.
+    char* optional_spaces(char* src);
+    char* optional_comment(char* src);
+    char* spaces_and_comments(char* src);
+
     // Match a CSS identifier.
     char* identifier(char* src);
     // Match CSS '@' keywords.
@@ -232,5 +239,47 @@ namespace Sass {
     char* prefix_match(char* src);
     char* suffix_match(char* src);
     char* substring_match(char* src);
+    // Match CSS combinators.
+    char* adjacent_to(char* src);
+    char* precedes(char* src);
+    char* parent_of(char* src);
+    char* ancestor_of(char* src);
+    
+    // Utility functions for finding and counting characters in a string.
+    template<char c>
+    char* find_first(char* src) {
+      while (*src && *src != c) ++src;
+      return *src ? src : 0;
+    }
+    template<prelexer mx>
+    char* find_first(char* src) {
+      while (*src && !mx(src)) ++src;
+      return *src ? src : 0;
+    }
+    template <char c>
+    unsigned int count_interval(char* beg, char* end) {
+      unsigned int counter = 0;
+      while (beg < end && *beg) {
+        if (*beg == c) ++counter;
+        ++beg;
+      }
+      return counter;
+    }
+    template <prelexer mx>
+    unsigned int count_interval(char* beg, char* end) {
+      unsigned int counter = 0;
+      while (beg < end && *beg) {
+        char* p;
+        if (p = mx(beg)) {
+          ++counter;
+          beg = p;
+        }
+        else {
+          ++beg;
+        }
+      }
+      return counter;
+    }
+    
   }
 }

src/unit-test-prelexer.cpp

 #include <cstdio>
+#include <iostream>
 #include "prelexer.hpp"
 
 using namespace Sass::Prelexer;
+using std::cout;
+using std::endl;
 
 void print_slice(const char *s, const char *t) {
   if (t) {
@@ -39,6 +42,10 @@ char dash1[]    = "|='bar'] { ... }";
 char pre1[]     = "^='hux'] { ... }";
 char suf1[]     = "$='baz'] { ... }";
 char sub1[]     = "*='bum'] { ... }";
+char ws1[]      = "  /* hello */\t\n//blah\n  /*blah*/ significant";
+
+extern const char slash_star[] = "/*";
+
 
 int main() {
   
@@ -60,6 +67,11 @@ int main() {
   check_twice(prefix_match, pre1, dash1);
   check_twice(suffix_match, suf1, pre1);
   check_twice(substring_match, sub1, suf1);
+  check_twice(spaces_and_comments, ws1, num1);
+  cout << count_interval<'\n'>(ws1, spaces_and_comments(ws1)) << endl;
+  cout << count_interval<'*'>(ws1, spaces_and_comments(ws1)) << endl;
+  cout << count_interval<exactly<slash_star> >(ws1, spaces_and_comments(ws1)) << endl;
+  putchar(*(find_first<'{'>(pre1))), putchar('\n');
 
   return 0;
 }
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