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