3 files changed, 26 insertions, 25 deletions

diff --git a/src/main.c b/src/main.c
index ac5e0f7..20134cd 100644
--- a/src/main.c
+++ b/src/main.c
@@ -25,13 +25,24 @@
 /// % Clear screen
 
 int main(int argc, char** argv) {
-    if (argc != 2) {
+    
+    FILE* file;
+
+    if (argc == 1) {
+        file = stdin;
+    } else if (argc == 2) {
+        file = fopen (argv[1], "r");
+        if (file == NULL) {
+            printf("error: failed to open %s (%s)\n", argv[1], strerror(errno));
+            exit(EXIT_FAILURE);
+        }
+    } else {
         printf("usage: brainfucked infile\n");
         return EXIT_FAILURE;
     }
-    
+
     Program program;
-    program_init(argv[1], &program);
+    program_init(file, &program);
     run_program(&program);
     program_free(&program);
 
diff --git a/src/program.c b/src/program.c
index dcec0f7..1d94da3 100644
--- a/src/program.c
+++ b/src/program.c
@@ -6,21 +6,17 @@
 #include <string.h>
 #include <errno.h>
 
-static FILE* f;
-static uint32_t count;
-
-static char next_char() {
+static char next_char(FILE* file) {
     char c;
-    if (fread(&c, 1, 1, f) != 1) {
+    if (fread(&c, 1, 1, file) != 1) {
         return EOF;
     } else {
-        count++;
         return c;
     }
 }
 
-static Symbol next_symbol() {
-    char c = next_char(); 
+static Symbol next_symbol(FILE* file) {
+    char c = next_char(file); 
 retest:
     switch (c) {
         case '<':
@@ -56,28 +52,21 @@ retest:
         case '\n':
         case '\t':
         case ' ':
-            while(c = next_char(), c == '\n' || c == '\t' || c == ' ');
+            while(c = next_char(file), c == '\n' || c == '\t' || c == ' ');
             goto retest;
         case '/':
-            while(c = next_char(), c != '\n' && c != EOF);
+            while(c = next_char(file), c != '\n' && c != EOF);
             goto retest;
         case EOF:
             return Eof;
         default:
-            c = next_char();
+            c = next_char(file);
             goto retest;
     }
 }
 
-void program_init(char* file_path, Program* program) {
-    f = fopen (file_path, "r");
-    if (f == NULL) {
-        printf("error: failed to open %s (%s)\n", file_path, strerror(errno));
-        exit(EXIT_FAILURE);
-    }
-
+void program_init(FILE* file, Program* program) {
     uint32_t capacity = 8;
-    count = 0;
 
     program->data = malloc(capacity * sizeof(Symbol));
     program->len = 0;
@@ -85,7 +74,7 @@ void program_init(char* file_path, Program* program) {
 
     Symbol s;
     while(true) {
-        s = next_symbol();
+        s = next_symbol(file);
         
         if (program->len == capacity) {
             capacity *= 2;
@@ -98,7 +87,7 @@ void program_init(char* file_path, Program* program) {
         if (s == Eof) break;
     }
 
-    fclose(f);
+    fclose(file);
 }
 
 void program_peek(Program* program, Symbol* symbol) {
diff --git a/src/program.h b/src/program.h
index 23f4d74..ea29b6c 100644
--- a/src/program.h
+++ b/src/program.h
@@ -2,6 +2,7 @@
 
 #include <stdbool.h>
 #include <stdint.h>
+#include <stdio.h>
 
 typedef enum {
     MoveLeft,
@@ -28,7 +29,7 @@ typedef struct {
     Symbol* data;
 } Program;
 
-void program_init(char* file_path, Program* program);
+void program_init(FILE* file, Program* program);
 void program_peek(Program* program, Symbol* symbol);
 void program_next(Program* program, Symbol* symbol);
 void program_last(Program* program, Symbol* symbol);