main.c

#include "defs.h"
#define extern_
#include "data.h"
#undef extern_
#include "decl.h"
#include <errno.h>

// Compiler setup and top-level execution
// Copyright (c) 2019 Warren Toomey, GPL3

// Initialise global variables
static void init() {
  Line = 1;
  Putback = '\n';
}

// Print out a usage if started incorrectly
static void usage(char *prog) {
  fprintf(stderr, "Usage: %s infile\n", prog);
  exit(1);
}

// Main program: check arguments and print a usage
// if we don't have an argument. Open up the input
// file and call scanfile() to scan the tokens in it.
void main(int argc, char *argv[]) {
  struct ASTnode *n;

  if (argc != 2)
    usage(argv[0]);

  init();

  if ((Infile = fopen(argv[1], "r")) == NULL) {
    fprintf(stderr, "Unable to open %s: %s\n", argv[1], strerror(errno));
    exit(1);
  }

  scan(&Token);			// Get the first token from the input
  n = binexpr();		// Parse the expression in the file
  printf("%d\n", interpretAST(n));	// Calculate the final result
  exit(0);
}