Add initial ast construction for fixnum/bool

1 files changed, 184 insertions, 14 deletions

diff --git a/src/bootstrap/main.c b/src/bootstrap/main.c
index 98f313b..b346cca 100755
--- a/src/bootstrap/main.c
+++ b/src/bootstrap/main.c
@@ -1,5 +1,7 @@
-#include <stdio.h>
 #include <ctype.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
 
 #include "shorthand.h"
 
@@ -15,6 +17,19 @@ sv_write(StringView sv) {
     }
 }
 
+bool
+sv_equal(StringView a, StringView b) {
+    if (a.n == b.n) {
+        for (size_t i = 0; i < a.n; i++) {
+            if (a.start[i] != b.start[i]) {
+                return false;
+            }
+        }
+        return true;
+    }
+    return false;
+}
+
 StringView
 read_line(void) {
     #define RL_BUF_SIZE 1024
@@ -121,6 +136,7 @@ tokenize(StringView sv) {
                     .n = 1,
                 };
             } break;
+            // TODO: Handle double quotes and escaped quotes.
             default: {
                 token_n++;
             } break;
@@ -134,23 +150,174 @@ tokenize(StringView sv) {
         };
     }
 
+    return (Tokens){.start = (StringView *)&tokens_buf, .n = n};
+}
+
+typedef enum ObjectType {
+    OBJ_TYPE_FIXNUM,
+    OBJ_TYPE_BOOL,
+    OBJ_TYPE_NIL,
+    OBJ_TYPE_SYMBOL,
+    OBJ_TYPE_STRING,
+    OBJ_TYPE_PAIR,
+    OBJ_TYPE_LIST,
+} ObjectType;
+
+typedef struct Object {
+    ObjectType type;
+    union {
+        // OBJ_TYPE_FIXNUM
+        ssize_t fixnum;
+
+        // OBJ_TYPE_BOOL
+        bool boolean;
+
+        // OBJ_TYPE_STRING
+        struct {
+            char *string;
+            size_t string_n;
+        };
+
+        // OBJ_TYPE_PAIR
+        struct {
+            struct Object *car;
+            struct Object *cdr;
+        };
+
+        // OBJ_TYPE_LIST
+        struct {
+            struct Object **list_elems;
+            size_t list_n;
+        };
+    };
+} Object;
+
+Object *
+make_fixnum(ssize_t num) {
+    Object *obj = malloc(sizeof(Object));
+    obj->type = OBJ_TYPE_FIXNUM;
+    obj->fixnum = num;
+    return obj;
+}
+
+Object *
+make_boolean(bool b) {
+    Object *obj = malloc(sizeof(Object));
+    obj->type = OBJ_TYPE_BOOL;
+    obj->boolean = b;
+    return obj;
+}
+
+Object *
+make_string(const char *str, size_t n) {
+    Object *obj = malloc(sizeof(Object));
+    obj->type = OBJ_TYPE_STRING;
+    obj->string = malloc(sizeof(char) * n);
+    memcpy(obj->string, str, n);
+    obj->string_n = n;
+    return obj;
+}
+
+Object *
+make_empty_list(void) {
+    Object *obj = malloc(sizeof(Object));
+    obj->type = OBJ_TYPE_LIST;
+    obj->list_elems = NULL;
+    obj->list_n = 0;
+    return obj;
+}
+
+void
+push_obj_to_list(Object *list, Object obj) {
+    assert(false && "todo: Not implemented");
+}
+
+bool
+token_is_fixnum(StringView token) {
+    for (size_t i = 0; i < token.n; i++) {
+        char c = token.start[i];
+        if (i == 0 && c == '-') {
+            continue;
+        }
+        if (!isdigit(c)) {
+            return false;
+        }
+    }
+    return true;
+}
+
+#define TRUE_TOKEN  (StringView){"true", 4}
+#define FALSE_TOKEN (StringView){"false", 5}
+
+Object *
+build_ast(Tokens tokens) {
     // DEBUG: Printing tokens.
-    printf("N_TOKENS: %ld\n", n);
-    for (size_t i = 0; i < n; i++) {
-        printf("TOKEN: ");
-        sv_write(tokens_buf[i]);
-        printf("\tN: %ld", tokens_buf[i].n);
-        printf("\n");
+    // printf("N_TOKENS: %ld\n", tokens.n);
+    // for (size_t i = 0; i < tokens.n; i++) {
+    //     printf("TOKEN: ");
+    //     sv_write(tokens.start[i]);
+    //     printf("\tN: %ld", tokens.start[i].n);
+    //     printf("\n");
+    // }
+
+    // TODO: Report error if we haven't consumed all the tokens?
+    for (size_t i = 0; i < tokens.n; i++) {
+        StringView token = tokens.start[i];
+
+        // OBJ_TYPE_FIXNUM
+        if (token_is_fixnum(token)) {
+            // Convert token to fixnum.
+            ssize_t num = 0;
+            int sign = 1;
+            for (size_t i = 0; i < token.n; i++) {
+                char c = token.start[i];
+                if (c == '-') {
+                    sign = -1;
+                    continue;
+                }
+                num = num * 10 + (c - '0');
+            }
+            return make_fixnum(num * sign);
+        }
+
+        // OBJ_TYPE_BOOL
+        if (sv_equal(token, TRUE_TOKEN)) {
+            return make_boolean(true);
+        }
+        if (sv_equal(token, FALSE_TOKEN)) {
+            return make_boolean(false);
+        }
     }
 
-    return (Tokens){.start = (StringView *)&tokens_buf, .n = n};
+    return NULL;
 }
 
 void
-display(StringView sv) {
-    if (sv.n != 0) {
-        sv_write(sv);
-        printf("\n");
+display(Object *root) {
+    if (root == NULL) {
+        return;
+    }
+
+    switch (root->type) {
+        case OBJ_TYPE_FIXNUM: {
+            printf("%zd", root->fixnum);
+        } break;
+        case OBJ_TYPE_BOOL: {
+            if (root->boolean) {
+                printf("true");
+            } else {
+                printf("false");
+            }
+        } break;
+        case OBJ_TYPE_NIL: {
+            printf("()");
+        } break;
+        case OBJ_TYPE_STRING: {
+            printf("\"%.*s\"", (int)root->string_n, root->string);
+        } break;
+        default: {
+            printf("TYPE NOT IMPLEMENTED FOR DISPLAY\n");
+        } break;
     }
 }
 
@@ -162,8 +329,11 @@ main(void) {
     while (true) {
         printf(REPL_PROMPT);
         StringView line = read_line();
-        tokenize(line);
-        display(line);
+        Object *ast = build_ast(tokenize(line));
+        if (ast) {
+            display(ast);
+            printf("\n");
+        }
     }
     return 0;
 }