Refactor into monorepo

1 files changed, 177 insertions, 0 deletions

diff --git a/pit/src/parser.c b/pit/src/parser.c
new file mode 100644
index 0000000..9c575cb
--- /dev/null
+++ b/pit/src/parser.c
@@ -0,0 +1,177 @@
+#include <lcq/pit/utils.h>
+#include <lcq/pit/lexer.h>
+#include <lcq/pit/parser.h>
+#include <lcq/pit/runtime.h>
+
+static pit_lex_token peek(pit_parser *st) {
+    if (!st) return PIT_LEX_TOKEN_ERROR;
+    return st->next.token;
+}
+
+static pit_lex_token advance(pit_parser *st) {
+    if (!st) return PIT_LEX_TOKEN_ERROR;
+    st->cur = st->next;
+    st->next.token = pit_lex_next(st->lexer);
+    st->next.start = st->lexer->start;
+    st->next.end = st->lexer->end;
+    st->next.line = st->lexer->start_line;
+    st->next.column = st->lexer->start_column;
+    return st->cur.token;
+}
+
+static bool match(pit_parser *st, pit_lex_token t) {
+    if (peek(st) == t) {
+        advance(st);
+        return true;
+    } else return false;
+}
+
+static void get_token_string(pit_parser *st, char *buf, i64 len) {
+    i64 diff = st->cur.end - st->cur.start;
+    i64 tlen = diff >= len ? len - 1 : diff;
+    pit_libc_string_memcpy((u8 *) buf, (u8 *) st->lexer->input + st->cur.start, (size_t) tlen);
+    buf[tlen] = 0;
+}
+
+static i64 digit_value(char c) {
+    if (c >= '0' && c <= '9') {
+        return c - '0';
+    } else if (c >= 'a' && c <= 'f') {
+        return c - 'a' + 10;
+    } else if (c >= 'A' && c <= 'F') {
+        return c - 'A' + 10;
+    } else {
+        return 0;
+    }
+}
+
+void pit_parser_from_lexer(pit_parser *ret, pit_lexer *lex) {
+    ret->lexer = lex;
+    ret->cur.token = ret->next.token = PIT_LEX_TOKEN_ERROR;
+    ret->cur.start = ret->next.start = 0;
+    ret->cur.end = ret->next.end = 0;
+    ret->cur.line = ret->next.line = -1;
+    ret->cur.column = ret->next.column = -1;
+    advance(ret);
+}
+
+/* parse a single expression */
+pit_value pit_parse(pit_runtime *rt, pit_parser *st, bool *eof) {
+    if (rt == NULL || st == NULL) return PIT_NIL;
+    pit_lex_token t = advance(st);
+    rt->source_line = st->cur.line;
+    rt->source_column = st->cur.column;
+    switch (t) {
+    case PIT_LEX_TOKEN_ERROR:
+        pit_error(rt, "encountered an error while lexing: %s", st->lexer->error);
+        return PIT_NIL;
+    case PIT_LEX_TOKEN_EOF:
+        if (eof != NULL) {
+            *eof = true;
+        } else {
+            pit_error(rt, "end-of-file while parsing");
+        }
+        return PIT_NIL;
+    case PIT_LEX_TOKEN_LPAREN: {
+        pit_value ret = PIT_NIL;
+        while (!match(st, PIT_LEX_TOKEN_RPAREN)) {
+            if (match(st, PIT_LEX_TOKEN_DOT)) {
+                ret = pit_parse(rt, st, eof);
+                if (match(st, PIT_LEX_TOKEN_RPAREN)) {
+                    break;
+                } else {
+                    pit_error(rt, "unterminated dotted list");
+                    return PIT_NIL;
+                }
+            } else {
+                ret = pit_value_cons(rt, pit_parse(rt, st, eof), ret);
+            }
+            if (rt->error != PIT_NIL || (eof != NULL && *eof)) {
+                pit_error(rt, "unterminated list");
+                return PIT_NIL; /* if we hit an error, stop!*/
+            }
+        }
+        ret = pit_value_list_reverse(rt, ret);
+        if (pit_value_sort(ret) == PIT_VALUE_SORT_REF) {
+            pit_annotation a = {0};
+            a.line = rt->source_line;
+            a.column = rt->source_column;
+            pit_annotation_set(rt, pit_value_as_ref(rt, ret), a);
+        }
+        return ret;
+    }
+    case PIT_LEX_TOKEN_LSQUARE: {
+        pit_value ret = PIT_NIL;
+        pit_value xs = PIT_NIL;
+        i64 len = 0;
+        while (!match(st, PIT_LEX_TOKEN_RSQUARE)) {
+            pit_value x = pit_parse(rt, st, eof);
+            xs = pit_value_cons(rt, x, xs);
+            len += 1;
+            if (rt->error != PIT_NIL || (eof != NULL && *eof)) {
+                pit_error(rt, "unterminated array literal");
+                return PIT_NIL;
+            }
+        }
+        ret = pit_value_array_new(rt, len);
+        while (xs != PIT_NIL) {
+            pit_value_array_set(rt, ret, --len, pit_value_cons_car(rt, xs));
+            xs = pit_value_cons_cdr(rt, xs);
+        }
+        return ret;
+    }
+    case PIT_LEX_TOKEN_QUOTE:
+        return pit_value_list(rt, 2, pit_symtab_intern_cstr(rt, "quote"), pit_parse(rt, st, eof));
+    case PIT_LEX_TOKEN_INTEGER_LITERAL: {
+        i64 idx = st->cur.start;
+        i64 base = 10;
+        i64 total = 0;
+        bool neg = false;
+        char c = st->lexer->input[idx++];
+        if (c == '-') {
+            neg = true;
+            if (idx < st->cur.end) {
+                c = st->lexer->input[idx++];
+            } else {
+                pit_error(rt, "malformed negative integer literal"); return PIT_NIL;
+            }
+        }
+        if (c == '0' && idx + 1 < st->cur.end) {
+            switch (st->lexer->input[idx++]) {
+            case 'b': base = 2; break;
+            case 'o': base = 8; break;
+            case 'x': base = 16; break;
+            default: pit_error(rt, "unknown integer base"); return PIT_NIL;
+            }
+        } else { total = digit_value(c); }
+        while (idx < st->cur.end) {
+            total *= base;
+            total += digit_value(st->lexer->input[idx++]);
+            if (total > 0x1ffffffffffff) {
+                pit_error(rt, "integer literal too large"); return PIT_NIL;
+            }
+        }
+        return pit_value_integer_new(rt, neg ? -total : total);
+    }
+    case PIT_LEX_TOKEN_STRING_LITERAL: {
+        char buf[256] = {0};
+        get_token_string(st, buf, sizeof(buf));
+        i64 len = (i64) pit_libc_string_strlen(buf);
+        i64 cur = 0;
+        for (i64 i = 1; i < len; ++i) {
+            if (buf[i] == '\\' && i + 1 < len) buf[cur++] = buf[++i];
+            else if (buf[i] != '"') buf[cur++] = buf[i];
+            else break;
+        }
+        return pit_value_bytes_new(rt, (u8 *) buf, cur);
+    }
+    case PIT_LEX_TOKEN_SYMBOL: {
+        char buf[256] = {0};
+        get_token_string(st, buf, sizeof(buf));
+        return pit_symtab_intern_cstr(rt, buf);
+    }
+    default:
+        pit_error(rt, "unexpected token: %s", pit_lex_token_name(t));
+        return PIT_NIL;
+    }
+}