feat: implement lexer+parser for example program

src/compiler/fzl_reader.c

@@ -0,0 +1,202 @@
+#include <compiler/fzl_reader.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+// Last error from reader
+static char last_err[256] = {0};
+
+fzl_reader_t *fzl_mkreader(char *source)
+{
+	fzl_reader_ll_t *first_node = malloc(sizeof(fzl_reader_ll_t));
+	first_node->token = NULL;
+	first_node->next = NULL;
+
+	fzl_reader_t *reader = malloc(sizeof(fzl_reader_t));
+	reader->first = first_node;
+	reader->last = first_node;
+	reader->source = source;
+	reader->position = 0;
+	reader->at_end = true;
+
+	return reader;
+}
+
+// --- Read zone ---
+
+// Try parse name
+fzl_token_t *parse_name(fzl_reader_t *reader)
+{
+	size_t lpos = reader->position;
+	size_t size = 0;
+
+	do
+	{
+		lpos++;
+		size++;
+	}
+	while ((reader->source[lpos] >= 'A' && reader->source[lpos] <= 'Z')
+			|| (reader->source[lpos] >= 'a' && reader->source[lpos] <= 'z'));
+
+	char *value = malloc(size);
+	memcpy(value, reader->source + reader->position, size);
+
+	size_t start = reader->position;
+	reader->position += size;
+
+	fzl_token_t *tok = fzl_mktoken(
+		FZL_TOKTYPE_NAME,
+		start,
+		reader->position - 1,
+		value,
+		size
+	);
+	free(value);
+
+	return tok;
+}
+
+// Try parse string literal
+fzl_token_t *parse_string_literal(fzl_reader_t *reader)
+{
+	size_t lpos = reader->position;
+	size_t size = 0;
+
+	if (reader->source[lpos] != '\'' && reader->source[lpos] != '"')
+		return NULL;
+
+	char open_symbol = reader->source[lpos];
+
+	do
+	{
+		lpos++;
+		size++;
+	}
+	while (reader->source[lpos] != open_symbol);
+	size++;
+
+	if (size == 2)
+	{
+		fzl_token_t *tok = fzl_mktoken(
+			FZL_TOKTYPE_STR_LITERAL,
+			reader->position,
+			reader->position + 1,
+			"",
+			0
+		);
+		return tok;
+	}
+
+	char *value = malloc(size - 2);
+	memcpy(value, reader->source + reader->position + 1, size - 2);
+	fzl_token_t *tok = fzl_mktoken(
+		FZL_TOKTYPE_STR_LITERAL,
+		reader->position,
+		lpos,
+		value,
+		size - 2
+	);
+	free(value);
+
+	reader->position += size;
+
+	return tok;
+}
+
+int fzl_read(fzl_reader_t *reader)
+{
+	const size_t len = strlen(reader->source);
+	if (reader->position >= len) return 0;
+	
+	do {
+		size_t p = reader->position;
+		fzl_token_t *token;
+		char curr = reader->source[p];
+
+		if (curr == '\n' || curr == ' ' || curr == '\r')
+		{
+			reader->position++;
+			continue;
+		}
+
+		if (curr == '\'' || curr == '"')
+			token = parse_string_literal(reader);
+		else if (curr == '(')
+		{
+			token = fzl_mktoken(
+				FZL_TOKTYPE_LPAIR,
+				p, p, NULL, 0);
+			reader->position++;
+		}
+		else if (curr == ')')
+		{
+			token = fzl_mktoken(
+				FZL_TOKTYPE_RPAIR,
+				p, p, NULL, 0);
+			reader->position++;
+		}
+		else if (curr >= 'A' && curr <= 'Z' ||
+						 curr >= 'a' && curr <= 'z')
+			token = parse_name(reader);
+		else
+		{
+			sprintf(last_err, "undefined token '%c'", curr);
+			return -1;
+		}
+
+		if (!token)
+		{
+			size_t line = 1, linepos = 1;
+			for (size_t i = 0; i < p; i++)
+			{
+				char sym = reader->source[i];
+				if (sym == '\n')
+				{
+					linepos = 1;
+					line++;
+				} else linepos++;
+			}
+
+			sprintf(last_err, "error parsing token (position %ld of line %ld)", line, linepos);
+			return -1;
+		}
+
+		fzl_reader_ll_t *tok_node = malloc(sizeof(fzl_reader_ll_t));
+		tok_node->token = token;
+		
+		reader->last->next = tok_node;
+		reader->last = tok_node;
+	} while (reader->position < len);
+
+	reader->at_end = true;
+	return 0;
+}
+
+// --- Read zone end ---
+
+char *fzl_reader_geterror()
+{
+	return last_err;
+}
+
+void free_node_and_next(fzl_reader_ll_t *node)
+{
+	if (!node) return;
+	if (node->next)
+		free_node_and_next(node->next);
+	
+	if (node->token)
+		fzl_freetoken(node->token);
+
+	free(node);
+}
+
+void fzl_freereader(fzl_reader_t *reader)
+{
+	if (!reader) return;
+	if (reader->first)
+		free_node_and_next(reader->first);
+	
+	free(reader);
+}
+