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#include <stdio.h>
#include <ctype.h>
#include "shorthand.h"
typedef struct StringView {
char *start;
size_t n;
} StringView;
void
sv_write(StringView sv) {
for (size_t i = 0; i < sv.n; i++) {
putchar(sv.start[i]);
}
}
StringView
read_line(void) {
#define RL_BUF_SIZE 1024
static char readline_buf[RL_BUF_SIZE];
// Clear buffer.
for (size_t i = 0; i < RL_BUF_SIZE; i++) {
readline_buf[i] = 0;
}
// Barebones readline implementation.
size_t n = 0;
char c;
while ((c = getchar()) != '\n') {
if (c == '\b') {
readline_buf[n] = '\0';
n--;
} else if (((u8)c >= 0x20 && (u8)c <= 0x7F) && n < RL_BUF_SIZE) {
readline_buf[n] = c;
n++;
}
}
return (StringView){.start = (char *)&readline_buf, .n = n};
}
typedef struct Tokens {
StringView *start;
size_t n;
} Tokens;
Tokens
tokenize(StringView sv) {
// NOTE: Not allocating any memory for now, but we are limited by a maximum
// number of tokens we can process.
#define TOKENS_BUF_SIZE 1024
static StringView tokens_buf[TOKENS_BUF_SIZE];
// Clear buffer.
for (size_t i = 0; i < TOKENS_BUF_SIZE; i++) {
tokens_buf[i] = (StringView){0};
}
size_t n = 0;
size_t token_n = 0;
for (size_t i = 0; i < sv.n; i++) {
switch (sv.start[i]) {
case ' ':
case '\f':
case '\n':
case '\r':
case '\t':
case '\v': {
if (token_n != 0) {
// Push token.
tokens_buf[n++] = (StringView){
.start = &sv.start[i - token_n],
.n = token_n,
};
token_n = 0;
}
continue;
} break;
case '(': {
if ((i + 1 < sv.n)) {
char next_c = sv.start[i + 1];
if (isspace(next_c)) {
fprintf(stderr, "error: lparen delimiter followed by space\n");
return (Tokens){0};
}
}
if (token_n != 0) {
fprintf(stderr, "error: lparen delimiter within symbol name\n");
return (Tokens){0};
}
// Push paren token.
tokens_buf[n++] = (StringView){
.start = &sv.start[i],
.n = 1,
};
} break;
case ')': {
if ((i + 1 < sv.n)) {
char next_c = sv.start[i + 1];
if ((next_c != ')' && !isspace(next_c))) {
fprintf(stderr, "error: rparen delimiter within symbol name\n");
return (Tokens){0};
}
}
if (token_n != 0) {
// Push previous token.
tokens_buf[n++] = (StringView){
.start = &sv.start[i - token_n],
.n = token_n,
};
token_n = 0;
}
// Push paren token.
tokens_buf[n++] = (StringView){
.start = &sv.start[i],
.n = 1,
};
} break;
default: {
token_n++;
} break;
}
}
if (token_n != 0) {
// End of line encountered.
tokens_buf[n++] = (StringView){
.start = &sv.start[sv.n - token_n],
.n = token_n,
};
}
// 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");
}
return (Tokens){.start = (StringView *)&tokens_buf, .n = n};
}
void
display(StringView sv) {
if (sv.n != 0) {
sv_write(sv);
printf("\n");
}
}
#define REPL_PROMPT "bdl> "
int
main(void) {
printf("BDL REPL (Press Ctrl-C to exit)\n");
while (true) {
printf(REPL_PROMPT);
StringView line = read_line();
tokenize(line);
display(line);
}
return 0;
}
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