igen: Start work on writing an instruction handler

generator.

This will make it easier in the long run to modify
instructions, add new instructions, and move the opcode
tables around.

1 files changed, 91 insertions, 0 deletions

diff --git a/igen/lexer.c b/igen/lexer.c
new file mode 100644
index 0000000..275bcdd
--- /dev/null
+++ b/igen/lexer.c
@@ -0,0 +1,91 @@
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "lexer.h"
+#include "misc.h"
+
+atom get_token_id(const char c, const int dbg) {
+	switch (c) {
+		case '(': return ATOM_LBRACK;
+		case ')': return ATOM_RBRACK;
+		case '/': return ATOM_SLASH;
+		case '+': return ATOM_PLUS;
+		case '-': return ATOM_MINUS;
+		case '*': return ATOM_ASTR;
+		case '%': return ATOM_PRCNT;
+		case '&': return ATOM_AMPR;
+		case '|': return ATOM_PIPE;
+		case '^': return ATOM_CARROT;
+		case '#': return ATOM_HASH;
+		case ':': return ATOM_COL;
+		case ';': return ATOM_SCOL;
+		case ' ': return ATOM_SPACE;
+		case '_': return ATOM_USCORE;
+		case '=': return ATOM_EQUAL;
+		case '.': return ATOM_DOT;
+		case '?': return ATOM_QMARK;
+		case '!': return ATOM_BANG;
+		case '<': return ATOM_LT;
+		case '>': return ATOM_GT;
+		case '%': return ATOM_PERCENT;
+		case ',': return ATOM_COMMA;
+		case '\\': return ATOM_BSLASH;
+		case '\"': return ATOM_QUOTE;
+		case '\'': return ATOM_SQUOTE;
+		case '\t': return ATOM_TAB;
+		case '\n': return ATOM_NLINE;
+		default:
+			if (isalpha(c)) {
+				return ATOM_ALPHA;
+			} else if (isdigit(c)) {
+				return ATOM_NUM;
+			}
+			break;
+	}
+	return ATOM_NONE;
+}
+
+int get_atom_span(const char *str, const atom *atoms, int inv, int dbg) {
+	int i;
+	for (i = 0; str[i] != '\0'; ++i) {
+		const enum atom atom = get_atom_id(str[i], dbg);
+		for (int j = 0; atoms[j] != ATOM_NONE; ++j) {
+			const int is_done = (inv) ? (atom == atoms[j]) : (atom != atoms[j]);
+			if (is_done) {
+				return i;
+			}
+		}
+	}
+	return i;
+}
+
+int lex(char *str, int dbg) {
+	int in_inst_stmt = 0;
+	lexeme *lex_start = NULL;
+	lexeme *lex_end = NULL;
+
+	for (int i = 0; str[i] != '\0'; ++i) {
+		atom atom_id = get_atom_id(str[i], dbg);
+		switch (atom_id) {
+			case ATOM_PERCENT:
+				if (get_atom_id(str[++i]) == ATOM_PERCENT) {
+					in_inst_stmt = !in_inst_stmt;
+				}
+				break;
+			case ATOM_LBRACK:
+				break;
+			case ATOM_ALPHA:
+				do {
+					const int ident_len = get_atom_span(&str[i], (const atom []) {
+						ATOM_ALPHA,
+						ATOM_USCORE,
+						ATOM_NUM,
+						ATOM_NONE
+					}, 0, dbg);
+					char *ident = calloc(ident_len+1, sizeof(char));
+				} while(0);
+				break;
+		}
+	}
+}