X-Git-Url: https://feistymeow.org/gitweb/?a=blobdiff_plain;f=infobase%2Fexamples%2Fcpp_grammar_code%2FCxxLexing.cxx;fp=infobase%2Fexamples%2Fcpp_grammar_code%2FCxxLexing.cxx;h=d57b0f1001a21033ae985f3df52c8494de5ff2d2;hb=c589a3686d4508c9c5ea7841deb9be251460ddc3;hp=0000000000000000000000000000000000000000;hpb=4c595ba63a6c5203e104fe83fee43d69d3ff7aef;p=feisty_meow.git

diff --git a/infobase/examples/cpp_grammar_code/CxxLexing.cxx b/infobase/examples/cpp_grammar_code/CxxLexing.cxx
new file mode 100644
index 00000000..d57b0f10
--- /dev/null
+++ b/infobase/examples/cpp_grammar_code/CxxLexing.cxx
@@ -0,0 +1,152 @@
+#ifdef FLEX_PP_CLASS
+FLEX_PP_CLASS theLexer;
+#define LEX_DOT theLexer .
+#else
+#define LEX_DOT
+#endif
+
+bool c_keywords = false;
+bool echo_line_numbers = false;
+bool echo_line_text = false;
+size_t line_number = 0;
+
+#ifdef NEEDS_YYWRAP
+int yywrap() { return 1; }
+#endif
+
+CxxToken *yylex_token()
+{
+	if (!LEX_DOT yylex())
+		return 0;
+	return yyToken;
+}
+
+//
+//	Configure the lexer to reflect successful parsing of a character value, assigning it to yylval.
+//
+//	The source someText[aLength] should correspond to the parsed text including any L or ' prefix
+//	but excluding any ' suffix. In this way the return can indicate whether a wide character has
+//	been detected and the routine can accommodate a variety of erroneous terminations.
+//
+CxxToken *make_character(const char *someText, size_t aLength)
+{
+	bool isWide = false;
+	if (someText && aLength)
+	{
+		if (*someText == 'L')
+		{
+			isWide = true;
+			someText++;
+			aLength--;
+		}
+		if (!aLength || (*someText != '\''))
+			ERRMSG("BUG - bad start of character literal.");
+		if (aLength)
+		{
+			someText++;
+			aLength--;
+		}
+	}
+	if (isWide)
+		return make_wide_character(someText, aLength);
+	else
+		return make_narrow_character(someText, aLength);
+}
+
+CxxToken *make_identifier(const char *someText, size_t aLength)
+{
+	return new CxxNaffToken(PARSE_TOKEN(Identifier), someText, aLength);
+}
+
+//
+//	Buffer the incoming line, before any characters are analysed.
+//
+void make_line(const char *yyText, size_t yyLeng)
+{
+	if (echo_line_text)
+		cout << tokenMarkDepth << ": "  << line_number << ": " << yyText << flush; 
+	else if (echo_line_numbers)
+		cout << line_number << endl; 
+	line_number++ ; 
+}
+
+CxxToken *make_literal_character(const char *someText, size_t aLength)
+{
+	return new CxxNaffToken(PARSE_TOKEN(CharacterLiteral), someText, aLength);
+}
+
+CxxToken *make_narrow_character(const char *someText, size_t aLength)
+{
+	return new CxxNaffToken(PARSE_TOKEN(CharacterLiteral), someText, aLength);
+}
+
+CxxToken *make_narrow_string(const char *someText, size_t aLength)
+{
+	return new CxxNaffToken(PARSE_TOKEN(StringLiteral), someText, aLength);
+}
+
+CxxToken *make_number(const char *someText, size_t aLength)
+{
+	return new CxxNaffToken(PARSE_TOKEN(IntegerLiteral), someText, aLength);
+}
+
+//
+//	Configure the lexer to reflect successful parsing of a categorised string.
+//
+//	The source someText[aLength] should correspond to the parsed text including any
+//	L or " prefix but excluding any " suffix. In this way the return can indicate whether a wide
+//	character has been detected and the routine can accommodate a variety of erroneous terminations.
+//
+CxxToken *make_string(const char *someText, size_t aLength)
+{
+	bool isWide = false;
+	if (someText && aLength)
+	{
+		if (*someText == 'L')
+		{
+			isWide = true;
+			someText++;
+			aLength--;
+		}
+		if (!aLength || (*someText != '"'))
+			ERRMSG("BUG - bad start of string literal.");
+		if (aLength)
+		{
+			someText++;
+			aLength--;
+		}
+	}
+	if (isWide)
+		return make_wide_string(someText, aLength);
+	else
+		return make_narrow_string(someText, aLength);
+}
+
+//
+//	Return the appropriate 1 of 256 flyweight tokens for the ASCII characters.
+//
+CxxToken *make_token(size_t tokenValue)
+{
+	static CxxToken *asciiTokens[256];
+	if (tokenValue >= (sizeof(asciiTokens)/sizeof(asciiTokens[0])))
+	{
+		ERRMSG("Cannot make_token for " << tokenValue);
+		return 0;
+	}
+	CxxToken **p = &asciiTokens[tokenValue];
+	CxxToken *theToken = *p;
+	if (!theToken)
+		*p = theToken = new CxxToken(tokenValue);
+	return theToken;
+}
+
+CxxToken *make_wide_character(const char *someText, size_t aLength)
+{
+	return new CxxNaffToken(PARSE_TOKEN(CharacterLiteral), someText, aLength);
+}
+
+CxxToken *make_wide_string(const char *someText, size_t aLength)
+{
+	return new CxxNaffToken(PARSE_TOKEN(StringLiteral), someText, aLength);
+}
+