calc

commit 89878fdbc63a7c562b91847e8020578822f9adbf
parent 7fe98576acd7ec303e7e88110942fa622e0d1aca
Author: amin <dev@aminmesbah.com>
Date:   Sat, 27 Oct 2018 05:23:21 +0000

Be parseful

FossilOrigin-Name: b95ce4ca2461de1db0a5575310fef8d2655224103828fd583ad14cd9226286e8
Diffstat:
M
calc.c
 | 
144
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

1 file changed, 144 insertions(+), 0 deletions(-)
diff --git a/calc.c b/calc.c
@@ -1,9 +1,12 @@
 #include <assert.h>
+#include <ctype.h>
 #include <stddef.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 
+#define global_variable static
+
 struct BufHdr {
     size_t cap;
     size_t len;
@@ -75,7 +78,148 @@ void buf_test(void)
     printf("\n");
 }
 
+enum TokenKind {
+    // first 128 values reserved to match up with ascii
+    TOKEN_INT = 128,
+    TOKEN_NAME,
+};
+
+struct Token {
+    enum TokenKind kind;
+    union {
+        uint64_t val;
+        struct {
+            const char *start;
+            const char *end;
+        };
+    };
+};
+
+global_variable struct Token g_token;
+global_variable const char *g_stream;
+
+void lex_next_token() {
+    switch(*g_stream)
+    {
+        case '0':
+        case '1':
+        case '2':
+        case '3':
+        case '4':
+        case '5':
+        case '6':
+        case '7':
+        case '8':
+        case '9': {
+            uint64_t val = 0;
+            while (isdigit(*g_stream))
+            {
+                val *= 10;
+                val += *g_stream++ - '0';
+            }
+            g_token.kind = TOKEN_INT;
+            g_token.val = val;
+            break;
+        }
+        case 'a':
+        case 'b':
+        case 'c':
+        case 'd':
+        case 'e':
+        case 'f':
+        case 'g':
+        case 'h':
+        case 'i':
+        case 'j':
+        case 'k':
+        case 'l':
+        case 'm':
+        case 'n':
+        case 'o':
+        case 'p':
+        case 'q':
+        case 'r':
+        case 's':
+        case 't':
+        case 'u':
+        case 'v':
+        case 'w':
+        case 'x':
+        case 'y':
+        case 'z':
+        case 'A':
+        case 'B':
+        case 'C':
+        case 'D':
+        case 'E':
+        case 'F':
+        case 'G':
+        case 'H':
+        case 'I':
+        case 'J':
+        case 'K':
+        case 'L':
+        case 'M':
+        case 'N':
+        case 'O':
+        case 'P':
+        case 'Q':
+        case 'R':
+        case 'S':
+        case 'T':
+        case 'U':
+        case 'V':
+        case 'W':
+        case 'X':
+        case 'Y':
+        case 'Z':
+        case '_': {
+            const char *start = g_stream++;
+            while (isalnum(*g_stream) || *g_stream == '_')
+            {
+                g_stream++;
+            }
+            g_token.kind = TOKEN_NAME;
+            g_token.start = start;
+            g_token.end = g_stream;
+            break;
+        }
+        default:
+            g_token.kind = *g_stream++;
+            break;
+    }
+}
+
+void print_token(struct Token token)
+{
+    switch(token.kind)
+    {
+        case TOKEN_INT:
+            printf("TOKEN_INT: %lu\n", token.val);
+            break;
+        case TOKEN_NAME:
+            printf("TOKEN_NAME: %.*s\n", (int)(token.end - token.start), token.start);
+            break;
+        default:
+            printf("TOKEN: '%c'\n", token.kind);
+            break;
+    }
+}
+
+void lex_test()
+{
+    char *source = "+()_HELLO1,234+FOO!994";
+    g_stream = source;
+    lex_next_token();
+    while (g_token.kind)
+    {
+        print_token(g_token);
+        lex_next_token();
+    }
+}
+
 int main(void)
 {
     buf_test();
+    lex_test();
 }