ragel-6.9ragel-6.9

1 files changed, 170 insertions, 0 deletions

diff --git a/examples/pullscan.rl b/examples/pullscan.rl
new file mode 100644
index 0000000..d9e8a57
--- /dev/null
+++ b/examples/pullscan.rl
@@ -0,0 +1,170 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define BUFSIZE 4096
+
+typedef struct _Scanner {
+	/* Scanner state. */
+    int cs;
+    int act;
+    int have;
+    int curline;
+    char *ts;
+    char *te;
+    char *p;
+    char *pe;
+    char *eof;
+	FILE *file;
+	int done;
+
+	/* Token data */
+	char *data;
+	int len;
+    int value;
+
+	char buf[BUFSIZE];
+} Scanner;
+
+
+%%{
+	machine Scanner;
+	write data;
+}%%
+
+void scan_init( Scanner *s, FILE *file )
+{
+	memset (s, '\0', sizeof(Scanner));
+	s->curline = 1;
+	s->file = file;
+	s->eof = 0;
+	%% write init;
+}
+
+#define TK_NO_TOKEN (-1)
+#define TK_ERR 128
+#define TK_EOF 129
+#define TK_Identifier 130
+#define TK_Number 131
+#define TK_String 132
+
+#define ret_tok( _tok ) token = _tok; s->data = s->ts
+
+int scan( Scanner *s )
+{
+	int token = TK_NO_TOKEN;
+	int space, readlen;
+
+	while ( 1 ) {
+		if ( s->p == s->pe ) {
+			printf("scanner: need more data\n");
+
+			if ( s->ts == 0 )
+				s->have = 0;
+			else {
+				/* There is data that needs to be shifted over. */
+				printf("scanner: buffer broken mid token\n");
+				s->have = s->pe - s->ts;
+				memmove( s->buf, s->ts, s->have );
+				s->te -= (s->ts-s->buf);
+				s->ts = s->buf;
+			}
+
+			s->p = s->buf + s->have;
+			space = BUFSIZE - s->have;
+
+			if ( space == 0 ) {
+				/* We filled up the buffer trying to scan a token. */
+				printf("scanner: out of buffer space\n");
+				return TK_ERR;
+			}
+
+			if ( s->done ) {
+				printf("scanner: end of file\n");
+				s->p[0] = 0;
+				readlen = 1;
+			}
+			else {
+				readlen = fread( s->p, 1, space, s->file );
+				if ( readlen < space )
+					s->done = 1;
+			}
+
+			s->pe = s->p + readlen;
+		}
+
+		%%{
+			machine Scanner;
+			access s->;
+			variable p s->p;
+			variable pe s->pe;
+			variable eof s->eof;
+
+			main := |*
+
+			# Identifiers
+			( [a-zA-Z_] [a-zA-Z0-9_]* ) =>
+				{ ret_tok( TK_Identifier ); fbreak; };
+
+			# Whitespace
+			[ \t\n];
+
+			'"' ( [^\\"] | '\\' any ) * '"' =>
+				{ ret_tok( TK_String ); fbreak; };
+
+			# Number
+			digit+ => 
+				{ ret_tok( TK_Number ); fbreak; };
+			
+			# EOF
+			0 =>
+				{ ret_tok( TK_EOF ); fbreak; };
+
+			# Anything else
+			any => 
+				{ ret_tok( *s->p ); fbreak; };
+
+			*|;
+
+			write exec;
+		}%%
+
+		if ( s->cs == Scanner_error )
+			return TK_ERR;
+
+		if ( token != TK_NO_TOKEN ) {
+			s->len = s->p - s->data;
+			return token;
+		}
+	}
+}
+
+
+int main (int argc, char** argv)
+{
+	Scanner ss;
+	int tok;
+
+	scan_init(&ss, stdin);
+
+	while ( 1 ) {
+		tok = scan (&ss);
+		if ( tok == TK_EOF ) {
+			printf ("parser: EOF\n");
+			break;
+		}
+		else if ( tok == TK_ERR ) {
+			printf ("parser: ERR\n");
+			break;
+		}
+		else {
+			printf ("parser: %d \"", tok);
+			fwrite ( ss.data, 1, ss.len, stdout );
+			printf ("\"\n" );
+		}
+	}
+
+	return 0;
+}
+
+