2.6 KiB
Unu
unu
(verb) (-hia) pull out, withdraw, draw out, extract.
Unu is a tool for extracting fenced code blocks from Markdown documents.
I always found documenting my projects annoying. Eventually I decided to start mixing the code and commentary using Markdown. Unu is the tool I use to extract the sources from the original files. I've found that this makes it easier for me to keep the commentary up to date, and has lead to better commented code.
The Code
First, headers:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
I use this for readability purposes.
#define KiB * 1024
The read_line
function is intended to read in a single line
into a target buffer. This considers a line to end with either
a \n
or EOF.
void read_line(FILE *file, char *line_buffer) {
int ch, count;
if (file == NULL || line_buffer == NULL)
{
printf("Error: file or line buffer pointer is null.");
exit(1);
}
ch = getc(file);
count = 0;
while ((ch != '\n') && (ch != EOF)) {
line_buffer[count] = ch;
count++;
ch = getc(file);
}
line_buffer[count] = '\0';
}
The line buffer needs to be big enough for the longest lines in your source files. Here it's set to 16KiB, which suffices for everything I've used Unu with so far.
char source[16 KiB];
Unu looks for Markdown style fenced blocks of code. It supports
both backticks and tildes for this. This will return 1
if the
line appears to be a start/stop of a fence, or 0
otherwise.
int fenced(char *s)
{
int a = strcmp(s, "```");
int b = strcmp(s, "~~~");
if (a == 0) return 1;
if (b == 0) return 1;
return 0;
}
The actual extract
function is straightforward.
- open the file
- read each line
- if in a fenced region, write the lines to stdout
- close the file
void extract(char *fname) {
char *buffer = (char *)source;
char fence[4];
FILE *fp;
int inBlock;
inBlock = 0;
fp = fopen(fname, "r");
if (fp == NULL)
return;
while (!feof(fp)) {
read_line(fp, buffer);
strncpy(fence, buffer, 3);
fence[3] = '\0';
if (fenced(fence)) {
if (inBlock == 0)
inBlock = 1;
else
inBlock = 0;
} else {
if ((inBlock == 1) && (strlen(buffer) != 0))
printf("%s\n", buffer);
}
}
fclose(fp);
}
And finally, the main routine, which just runs extract
on
each specified file.
int main(int argc, char **argv) {
int i = 1;
if (argc > 1) {
while (i < argc) {
extract(argv[i++]);
}
}
else
printf("unu\n(c) 2013-2019 charles childers\n\nTry:\n %s filename\n", argv[0]);
return 0;
}