Report missing lexical action handlers from Lexer::valid()

src/lalr/ErrorCode.hpp

@@ -12,6 +12,7 @@ enum ErrorCode
     PARSER_ERROR_NONE, ///< No %error.
     LALR_ERROR_SYNTAX, ///< Syntax %error occured while parsing input.
     LALR_ERROR_UNTERMINATED_LITERAL, ///< Unterminated literal in an lalr grammar.
+    LEXER_ERROR_MISSING_ACTION_HANDLER, ///< A lexer action hasn't been bound to a function.
     LEXER_ERROR_SYNTAX, ///< Syntax %error occured while parsing some input.
     LEXER_ERROR_SYMBOL_CONFLICT, ///< A lexer state matches more than one symbol.
     LEXER_ERROR_LEXICAL_ERROR, ///< A lexical error occured while scanning an input sequence.

src/lalr/Lexer.hpp

@@ -54,6 +54,7 @@ public:
     const void* symbol() const;
     const Iterator& position() const;
     bool full() const;
+    bool valid() const;
     void set_action_handler( const char* identifier, LexerActionFunction function );
     void reset( Iterator start, Iterator finish );
     void advance();

src/lalr/Lexer.ipp

@@ -160,6 +160,45 @@ bool Lexer<Iterator, Char, Traits, Allocator>::full() const
     return full_;
 }
 
+/**
+// Is this Lexer valid?
+//
+// Reports errors for any action handlers that haven't been set.
+//
+// @return
+//  True if this Lexer is valid and can be used to split input into tokens
+//  otherwise false.
+*/
+template <class Iterator, class Char, class Traits, class Allocator>
+bool Lexer<Iterator, Char, Traits, Allocator>::valid() const
+{
+    bool valid = true;
+
+    for ( const LexerActionHandler& handler : action_handlers_ )
+    {
+        if ( !handler.function_ )
+        {
+            const LexerAction* action = handler.action_;
+            LALR_ASSERT( action );
+            fire_error( -1, -1, LEXER_ERROR_MISSING_ACTION_HANDLER, "Lexical action '%s' has no handler", action->identifier );
+            valid = false;
+        }
+    }
+
+    for ( const LexerActionHandler& handler : whitespace_action_handlers_ )
+    {
+        if ( !handler.function_ )
+        {
+            const LexerAction* action = handler.action_;
+            LALR_ASSERT( action );
+            fire_error( -1, -1, LEXER_ERROR_MISSING_ACTION_HANDLER, "Lexical action '%s' has no handler", action->identifier );
+            valid = false;
+        }
+    }
+
+    return valid;
+}
+
 /**
 // Set the action handler for \e identifier to \e function.
 //