initial

Makefile

@@ -0,0 +1,5 @@
+CC = clang
+CFLAGS = -Wall -Wextra -std=c99 -pedantic
+
+makros: makros.c
+	$(CC) $(CFLAGS) $< -o $@

makros.c

@@ -0,0 +1,173 @@
+#define _POSIX_C_SOURCE 2 /* popen */
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <libgen.h>
+#include <sys/stat.h>
+#include <time.h>
+
+typedef struct {
+    char ident[80];
+    char value[256]; // TODO: variable size values
+} makro;
+
+FILE *IN;
+FILE *OUT;
+size_t makro_num = 0;
+makro makros[10] = {0}; // TODO: remove limitation of max 10 makros per file
+
+void
+readn(size_t n, char *buf)
+{
+    for (size_t i = 0; i < n; i++)
+        buf[i] = fgetc(IN);
+}
+
+void
+die(const char *s, ...)
+{
+    va_list argp;
+    va_start(argp, s);
+    vfprintf(stderr, s, argp);
+    fputc('\n', stderr);
+    va_end(argp);
+    exit(1);
+}
+
+void
+shell_output(const char *cmd, char *out)
+{
+    FILE *shell_out = popen(cmd, "r");
+    if (shell_out == NULL)
+        die("couldn't execute command: %s", cmd);
+
+    char lastc = fgetc(shell_out), c;
+    size_t i = 0;
+    if (lastc != EOF) {
+        while ((c = fgetc(shell_out)) != EOF) {
+            out[i++] = lastc;
+            lastc = c;
+        }
+    }
+
+    pclose(shell_out);
+}
+
+void
+add_special_makros(const char *filename)
+{
+    makro_num = 2;
+
+    memcpy(makros[0].ident, "FILE_NAME", strlen("FILE_NAME"));
+    memcpy(makros[0].value, filename, strlen(filename));
+
+    memcpy(makros[1].ident, "FILE_LAST_CHANGED", strlen("FILE_LAST_CHANGED"));
+    struct stat attrib;
+    stat(filename, &attrib);
+    char date[20];
+    strftime(date, 20, "%Y-%m-%d", localtime(&(attrib.st_ctime)));
+    memcpy(makros[1].value, date, strlen(date));
+}
+
+void
+define_makro(makro *m, char *lastc)
+{
+    char buf[7];
+    readn(6, buf);
+    buf[6] = '\0';
+    if (strcmp(buf, "makro ")) {
+        fputc('#', OUT);
+        fseek(IN, -6L, SEEK_CUR);
+        *lastc = '#';
+        return;
+    }
+
+    *lastc = '\n';
+
+    char *assops = "=@";
+    size_t i = 0;
+    char c;
+    while ((c = fgetc(IN)) && strchr(assops, c) == NULL) {
+        m->ident[i++] = c;
+        if (c == EOF || c == '\n')
+            die("makro definition missing assignment operator");
+    }
+    i = 0;
+
+    switch (c) {
+    case '=':
+        while ((c = fgetc(IN)) != '\n') {
+            m->value[i++] = c;
+            if (c == EOF)
+                die("makro definition missing assignment operator");
+        }
+        break;
+    case '@': {
+        char buf[256] = {0};
+        while ((c = fgetc(IN)) != '\n') {
+            buf[i++] = c;
+            if (c == EOF)
+                die("makro definition missing assignment operator");
+        }
+        shell_output(buf, m->value);
+        break;
+    }
+    default:
+        die("invalid operator: %c", c);
+    }
+}
+
+int
+main(int argc, char *argv[])
+{
+    switch (argc) {
+    case 1:
+        IN = stdin;
+        OUT = stdout;
+        break;
+    case 2:
+        IN = fopen(argv[1], "r");
+        OUT = stdout;
+        break;
+    case 3:
+        IN = fopen(argv[1], "r");
+        OUT = fopen(argv[2], "w");
+        break;
+    default:
+        die("usage: makros [input-file] [output-file]");
+    }
+
+    /* special makros */
+    add_special_makros(argv[1] ? argv[1] : "unknown");
+
+    char lastc = '\n', c;
+    while ((c = fgetc(IN)) != EOF) {
+        if (c == '#' && lastc == '\n') {
+            define_makro(&makros[makro_num++], &lastc);
+            if (lastc == '\n')
+                continue;
+        }
+
+        int found_makro = 0;
+        for (size_t i = 0; i < makro_num; i++) {
+            if (c == makros[i].ident[0]) {
+                char buf[80] = {0};
+                long len = strlen(makros[i].ident)-1;
+                readn(len, buf);
+                if (!strcmp(buf, makros[i].ident+1)) {
+                    fprintf(OUT, "%s", makros[i].value);
+                    found_makro = 1;
+                    break;
+                }
+                else {
+                    fseek(IN, -len, SEEK_CUR);
+                }
+            }
+        }
+        if (!found_makro) {
+            fputc(c, OUT);
+            lastc = c;
+        }
+    }
+}

readme

@@ -0,0 +1,12 @@
+#makro TEXT=random text
+makros is a simple macro tool, in a similar vein to the C preprocessor. However,
+in addition to storing TEXT in macros, it supports storing shell command output
+in them as well to allow for more flexibility. This readme file is an example of
+a raw file you can feed into makros. Try compiling the program by running
+`make' and run the command `./makros readme' to see how it works.
+
+#makro DATE@date +%s
+This readme was compiled at DATE.
+We have some *special* macros available, which give us some file reflection:
+File last changed FILE_LAST_CHANGED.
+This file is named FILE_NAME.