From 376b83e6a44271599ed563e3510b2411beab5921 Mon Sep 17 00:00:00 2001
From: Bad Diode <bd@badd10de.dev>
Date: Sat, 9 Oct 2021 13:46:54 +0200
Subject: Enable eval expressions from stdin and small cleanup

---
 src/bootstrap/main.c | 108 +++++++++++++++++++++------------------------------
 1 file changed, 45 insertions(+), 63 deletions(-)

diff --git a/src/bootstrap/main.c b/src/bootstrap/main.c
index e0012eb..f5653d6 100755
--- a/src/bootstrap/main.c
+++ b/src/bootstrap/main.c
@@ -36,8 +36,10 @@ sv_equal(StringView a, StringView b) {
     return false;
 }
 
+#define READLINE_VALID_CHAR(C) (((u8)(C) >= 0x20 && (u8)(C) < 0x7F) || (C) == '\n')
+
 StringView
-read_line(void) {
+read_line(FILE *fd, char delimiter) {
     #define RL_BUF_SIZE 1024
     static char readline_buf[RL_BUF_SIZE];
 
@@ -49,11 +51,11 @@ read_line(void) {
     // Barebones readline implementation.
     size_t n = 0;
     char c;
-    while ((c = getchar()) != '\n') {
+    while ((c = getc(fd)) != delimiter) {
         if (c == '\b') {
             readline_buf[n] = '\0';
             n--;
-        } else if (((u8)c >= 0x20 && (u8)c <= 0x7F) && n < RL_BUF_SIZE) {
+        } else if (READLINE_VALID_CHAR(c) && n < RL_BUF_SIZE) {
             readline_buf[n] = c;
             n++;
         }
@@ -697,30 +699,20 @@ eval(Object *root) {
 }
 
 void
-print_usage(void) {
-    printf("Usage: %s [options] <filename>\n", BIN_NAME);
-    printf("\n");
-    printf("\t-i\tInteractive mode (REPL).\n");
-    printf("\n");
-}
-
-void
-run_repl(void) {
-    printf("BDL REPL (Press Ctrl-C to exit)\n");
-    while (true) {
-        printf(REPL_PROMPT);
-        StringView line = read_line();
-        Tokens tokens = tokenize(line);
+eval_line(FILE *fd, char delimiter) {
+    StringView line = read_line(fd, delimiter);
+    Tokens tokens = tokenize(line);
 #if DEBUG
-        printf("N_TOKENS: %ld\n", tokens.n);
-        for (size_t i = 0; i < tokens.n; i++) {
-            printf("\tTYPE: %3d    ", tokens.start[i].type);
-            printf("N: %3ld    ", tokens.start[i].value.n);
-            printf("VALUE: ");
-            sv_write(tokens.start[i].value);
-            printf("\n");
-        }
+    printf("N_TOKENS: %ld\n", tokens.n);
+    for (size_t i = 0; i < tokens.n; i++) {
+        printf("\tTYPE: %3d    ", tokens.start[i].type);
+        printf("N: %3ld    ", tokens.start[i].value.n);
+        printf("VALUE: ");
+        sv_write(tokens.start[i].value);
+        printf("\n");
+    }
 #endif
+    while (tokens.n > 0) {
         Object *ast = parse(&tokens);
         if (ast) {
 #if DEBUG
@@ -735,53 +727,36 @@ run_repl(void) {
     }
 }
 
+void
+run_repl(void) {
+    printf("BDL REPL (Press Ctrl-C to exit)\n");
+    while (true) {
+        printf(REPL_PROMPT);
+        eval_line(stdin, '\n');
+    }
+}
+
 void
 run_file(char *file_name) {
 #if DEBUG
     printf("Executing file: %s\n", file_name);
 #endif
-
-    // Load entire file into memory.
-    char * src = NULL;
     FILE *fd = fopen(file_name, "r");
     if (!fd) {
         fprintf(stderr, "couldn't open file: %s\n", file_name);
-        exit(-1);
-    }
-    fseek(fd, 0, SEEK_END);
-    size_t file_size = ftell(fd);
-    fseek(fd, 0, SEEK_SET);
-    src = malloc(file_size + 1);
-    fread(src, 1, file_size, fd);
-    src[file_size] = '\0';
-    fclose(fd);
-
-    Tokens tokens = tokenize((StringView){.start = src, .n = file_size});
-#if DEBUG
-    printf("N_TOKENS: %ld\n", tokens.n);
-    for (size_t i = 0; i < tokens.n; i++) {
-        printf("\tTYPE: %3d    ", tokens.start[i].type);
-        printf("N: %3ld    ", tokens.start[i].value.n);
-        printf("VALUE: ");
-        sv_write(tokens.start[i].value);
-        printf("\n");
-    }
-#endif
-    while (tokens.n) {
-        Object *ast = parse(&tokens);
-        if (ast) {
-#if DEBUG
-            printf("AST: ");
-            display(ast);
-            printf("\n");
-            printf("EVAL: ");
-#endif
-            display(eval(ast));
-            printf("\n");
-        }
+        exit(EXIT_FAILURE);
     }
+    eval_line(fd, EOF);
+    fclose(fd);
+}
 
-    free(src);
+void
+print_usage(void) {
+    printf("Usage: %s [options] <filename>\n", BIN_NAME);
+    printf("\n");
+    printf("\t-i\tInteractive mode (REPL).\n");
+    printf("\t-x\tExecute expression from stdin.\n");
+    printf("\n");
 }
 
 int
@@ -789,12 +764,18 @@ main(int argc, char *argv[]) {
     init();
 
     int option;
-    while ((option = getopt(argc, argv, "i")) != -1) {
+    while ((option = getopt(argc, argv, "ix")) != -1) {
         switch (option) {
             case 'i': {
+                // Interactive mode.
                 run_repl();
                 return EXIT_SUCCESS;
             } break;
+            case 'x': {
+                // Execute expression from stdin.
+                eval_line(stdin, EOF);
+                return EXIT_SUCCESS;
+            } break;
             default: {
                 print_usage();
                 return EXIT_FAILURE;
@@ -802,6 +783,7 @@ main(int argc, char *argv[]) {
         }
     }
 
+    // Run from file.
     if (optind != argc - 1) {
         fprintf(stderr, "%s: No input file given.\n", BIN_NAME);
         print_usage();
-- 
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