ragel-6.9ragel-6.9

1 files changed, 116 insertions, 0 deletions

diff --git a/examples/awkemu.rl b/examples/awkemu.rl
new file mode 100644
index 0000000..6615943
--- /dev/null
+++ b/examples/awkemu.rl
@@ -0,0 +1,116 @@
+/*
+ * Perform the basic line parsing of input performed by awk.
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+%%{
+	machine awkemu;
+
+	action start_word {
+		ws[nwords] = fpc;
+	}
+
+	action end_word {
+		we[nwords++] = fpc;
+	}
+
+	action start_line {
+		nwords = 0;
+		ls = fpc;
+	}
+
+	action end_line {
+		printf("endline(%i): ", nwords );
+		fwrite( ls, 1, p - ls, stdout );
+		printf("\n");
+
+		for ( i = 0; i < nwords; i++ ) {
+			printf("  word: ");
+			fwrite( ws[i], 1, we[i] - ws[i], stdout );
+			printf("\n");
+		}
+	}
+
+	# Words in a line.
+	word = ^[ \t\n]+;
+
+	# The whitespace separating words in a line.
+	whitespace = [ \t];
+
+	# The components in a line to break up. Either a word or a single char of
+	# whitespace. On the word capture characters.
+	blineElements = word >start_word %end_word | whitespace;
+
+	# Star the break line elements. Just be careful to decrement the leaving
+	# priority as we don't want multiple character identifiers to be treated as
+	# multiple single char identifiers.
+	line = ( blineElements** '\n' ) >start_line @end_line;
+
+	# Any number of lines.
+	main := line*;
+}%%
+
+%% write data noerror nofinal;
+
+#define MAXWORDS 256
+#define BUFSIZE 4096
+char buf[BUFSIZE];
+
+int main()
+{
+	int i, nwords = 0;
+	char *ls = 0;
+	char *ws[MAXWORDS];
+	char *we[MAXWORDS];
+
+	int cs;
+	int have = 0;
+
+	%% write init;
+
+	while ( 1 ) {
+		char *p, *pe, *data = buf + have;
+		int len, space = BUFSIZE - have;
+		/* fprintf( stderr, "space: %i\n", space ); */
+
+		if ( space == 0 ) { 
+			fprintf(stderr, "buffer out of space\n");
+			exit(1);
+		}
+
+		len = fread( data, 1, space, stdin );
+		/* fprintf( stderr, "len: %i\n", len ); */
+		if ( len == 0 )
+			break;
+
+		/* Find the last newline by searching backwards. This is where 
+		 * we will stop processing on this iteration. */
+		p = buf;
+		pe = buf + have + len - 1;
+		while ( *pe != '\n' && pe >= buf )
+			pe--;
+		pe += 1;
+
+		/* fprintf( stderr, "running on: %i\n", pe - p ); */
+
+		%% write exec;
+
+		/* How much is still in the buffer. */
+		have = data + len - pe;
+		if ( have > 0 )
+			memmove( buf, pe, have );
+
+		/* fprintf(stderr, "have: %i\n", have ); */
+
+		if ( len < space )
+			break;
+	}
+
+	if ( have > 0 )
+		fprintf(stderr, "input not newline terminated\n");
+	return 0;
+}