Read-Back Extension

Decoding extension for Implementation of Closed Reduction using Interaction Nets Compiler:

${
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

char *var(int fresh);
char *append(char *format, char *buf, char *str);

#define ABST(BUF, STR) append("%s%s: ", (BUF), (STR))
#define APPL(BUF, STR) append("%s%s ", (BUF), (STR))
#define ATOM(BUF, STR) append("%s(%s)", (BUF), (STR))
}$

\print {
	/* Output results of read-back. */
	puts(RVAL);
	exit(EXIT_SUCCESS);
} \atom;

\read[a] {
	/* Read back abstraction. */
} \lambda[\atom_{var(1)}, \read_{ABST(LVAL, var(0))}(a)];

\lambda[\read_{APPL(strdup(""), RVAL)}(a), a] {
	/* Read back application. */
} \atom;

\read[\atom_{ATOM(LVAL, RVAL)}] {
	/* Read back an atom. */
} \atom;

\bind[a, \atom_{RVAL}, a] {
	/* Bind variable to an atom. */
} \atom;

\copy[\atom_{RVAL}, \atom_{strdup(RVAL)}] {
	/* Copy an atom. */
} \atom;

\dup[\atom_{RVAL}, \atom_{strdup(RVAL)}] {
	/* Duplicate an atom. */
} \atom;

\erase {
	/* Erase an atom. */
	free(RVAL);
} \atom;

$$

term = \read_{strdup("")}(\print);
term = {"Encoding"};

$$

char *var(int fresh)
{
	static int id;

	char buf[BUFSIZ];

	if (fresh)
		++id;

	sprintf(buf, "v%d", id);
	return strdup(buf);
}

char *append(char *format, char *buf, char *str)
{
	size_t size = strlen(format) + strlen(str);
	char *result = malloc(strlen(buf) + size);

	sprintf(result, format, buf, str);

	free(buf);
	free(str);
	return result;
}