1 files changed, 94 insertions, 0 deletions
diff --git a/runtime/doc/doctags.c b/runtime/doc/doctags.c
new file mode 100644
index 0000000..8822dcb
--- /dev/null
+++ b/runtime/doc/doctags.c
@@ -0,0 +1,94 @@
+/* vim:set ts=4 sw=4:
+ *
+ * This program makes a tags file for help text.
+ *
+ * Usage: doctags *.txt ... >tags
+ *
+ * A tag in this context is an identifier between stars, e.g. *c_files*
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <ctype.h>
+#include <stdlib.h>
+
+#define LINELEN 200
+
+	int
+main(int argc, char **argv)
+{
+	char	line[LINELEN];
+	char	*p1, *p2;
+	char	*p;
+	FILE	*fd;
+	int		len;
+	int		in_example;
+
+	if (argc <= 1)
+	{
+		fprintf(stderr, "Usage: doctags docfile ... >tags\n");
+		exit(1);
+	}
+	printf("help-tags\ttags\t1\n");
+	while (--argc > 0)
+	{
+		++argv;
+		fd = fopen(argv[0], "r");
+		if (fd == NULL)
+		{
+			fprintf(stderr, "Unable to open %s for reading\n", argv[0]);
+			continue;
+		}
+		in_example = 0;
+		while (fgets(line, LINELEN, fd) != NULL)
+		{
+			if (in_example)
+			{
+				// skip over example; non-blank in first column ends example
+				if (strchr(" \t\n\r", line[0]) != NULL)
+					continue;
+				in_example = 0;
+			}
+			p1 = strchr(line, '*');				// find first '*'
+			while (p1 != NULL)
+			{
+				p2 = strchr(p1 + 1, '*');		// find second '*'
+				if (p2 != NULL && p2 > p1 + 1)	// skip "*" and "**"
+				{
+					for (p = p1 + 1; p < p2; ++p)
+						if (*p == ' ' || *p == '\t' || *p == '|')
+							break;
+					// Only accept a *tag* when it consists of valid
+					// characters, there is white space before it and is
+					// followed by a white character or end-of-line.
+					if (p == p2
+							&& (p1 == line || p1[-1] == ' ' || p1[-1] == '\t')
+								&& (strchr(" \t\n\r", p[1]) != NULL
+									|| p[1] == '\0'))
+					{
+						*p2 = '\0';
+						++p1;
+						printf("%s\t%s\t/*", p1, argv[0]);
+						while (*p1)
+						{
+							// insert backslash before '\\' and '/'
+							if (*p1 == '\\' || *p1 == '/')
+								putchar('\\');
+							putchar(*p1);
+							++p1;
+						}
+						printf("*\n");
+						p2 = strchr(p2 + 1, '*');		// find next '*'
+					}
+				}
+				p1 = p2;
+			}
+			len = strlen(line);
+			if ((len == 2 && strcmp(&line[len - 2], ">\n") == 0)
+					|| (len >= 3 && strcmp(&line[len - 3], " >\n") == 0))
+				in_example = 1;
+		}
+		fclose(fd);
+	}
+	return 0;
+}