init

lex.c

@@ -0,0 +1,232 @@
+#include "lex.h"
+
+#include "util.h"
+
+typedef struct Pos {
+	size_t ln, col;     /* current position */
+	size_t m_ln, m_col; /* marked position */
+} Pos;
+
+static void consume(Pos *p, char c);
+static void emit(TokList *toks, const Pos *p, Tok t);
+static void mark(Pos *p);
+static void mark_err(const Pos *p);
+
+static void consume(Pos *p, char c) {
+	if (c == '\n') {
+		p->ln++;
+		p->col = 1;
+	} else
+		p->col++;
+}
+
+static void emit(TokList *toks, const Pos *p, Tok t) {
+	t.ln  = p->m_ln;
+	t.col = p->m_col;
+	toklist_append(toks, t);
+}
+
+static void mark(Pos *p) {
+	p->m_ln  = p->ln;
+	p->m_col = p->col;
+}
+
+static void mark_err(const Pos *p) {
+	err_ln  = p->m_ln;
+	err_col = p->m_col;
+}
+
+TokList lex(const char *s) {
+	TokList toks;
+	toklist_init(&toks);
+	Pos pos = { .ln = 1, .col = 1 };
+	for (;;) {
+		mark(&pos);
+		mark_err(&pos);
+
+		if (IS_ALPHA(s[0])) {
+			size_t i = 1;
+			const char *start = s;
+			consume(&pos, *(s++));
+			while (IS_ALNUM(s[0])) {
+				consume(&pos, *(s++));
+				i++;
+			}
+			if (streq_0_n("if", start, i))
+				emit(&toks, &pos, (Tok){ .kind = TokIf });
+			else if (streq_0_n("while", start, i))
+				emit(&toks, &pos, (Tok){ .kind = TokWhile });
+			else {
+				emit(&toks, &pos, (Tok){
+						.kind = TokIdent,
+						.Ident = {
+							.kind = IdentName,
+							.Name = sndup(start, i),
+						},
+					});
+			}
+			continue;
+		}
+
+		if (IS_NUM(s[0]) || s[0] == '.') {
+			const char *start = s;
+			size_t base = 10;
+			bool num_end = false;
+			bool is_float = false;
+			if (s[0] == '0') {
+				consume(&pos, *(s++));
+				if (s[0] == 'x' || s[0] == 'X') {
+					base = 16;
+					consume(&pos, *(s++));
+					start = s;
+				} else if (s[0] == 'b' || s[0] == 'B') {
+					base = 2;
+					consume(&pos, *(s++));
+					start = s;
+				} else if (!IS_NUM(s[0]) && s[0] != '.')
+					num_end = true;
+			}
+			if (!num_end) {
+				for (;;) {
+					if (s[0] == '.') {
+						if (is_float) {
+							mark(&pos);
+							mark_err(&pos);
+							set_err("Too many decimal points in number");
+							return toks;
+						}
+						if (base != 10) {
+							set_err("Only decimal floats are supported");
+							return toks;
+						}
+						is_float = true;
+					} else if (!IS_ALNUM(s[0]))
+						break;
+					consume(&pos, *(s++));
+				}
+			}
+
+			if (is_float) {
+				ssize_t endpos;
+				double num = stod(start, s - start, &endpos);
+				if (endpos != -1) {
+					err_col += endpos;
+					set_err("Invalid decimal float character: '%c'", start[endpos]);
+					return toks;
+				}
+
+				emit(&toks, &pos, (Tok){
+						.kind = TokVal,
+						.Val = {
+							.type = {
+								.kind = TypeFloat,
+							},
+							.Float = num,
+						},
+					});
+			} else {
+				ssize_t endpos;
+				intmax_t num = stoimax(start, s - start, base, &endpos);
+				if (endpos != -1) {
+					err_col += endpos;
+					set_err("Invalid base %zu numerical character: '%c'", base, start[endpos]);
+					return toks;
+				}
+
+				emit(&toks, &pos, (Tok){
+						.kind = TokVal,
+						.Val = {
+							.type = {
+								.kind = TypeInt,
+							},
+							.Int = num,
+						},
+					});
+			}
+			continue;
+		}
+
+		switch (s[0]) {
+			case 0:
+				goto end_of_file;
+			case ' ':
+			case '\t':
+				break;
+			case '\n':
+				emit(&toks, &pos, (Tok){
+						.kind = TokOp,
+						.Op = OpNewLn,
+					});
+				break;
+			case ':':
+				consume(&pos, *(s++));
+				if (s[0] == '=') {
+					emit(&toks, &pos, (Tok){ .kind = TokDeclare });
+				} else {
+					set_err("Expected ':='");
+					return toks;
+				}
+				break;
+			case '=':
+				emit(&toks, &pos, (Tok){ .kind = TokAssign });
+				break;
+			case '{':
+			case '}':
+			case '(':
+			case ')':
+			case ',':
+			case '+':
+			case '-':
+			case '*':
+				emit(&toks, &pos, (Tok){
+						.kind = TokOp,
+						.Op = s[0],
+					});
+				break;
+			case '/':
+				consume(&pos, *(s++));
+				if (s[0] == '/') {
+					consume(&pos, *(s++));
+					while (s[0] != '\n') {
+						if (s[0] == 0)
+							goto end_of_file;
+						consume(&pos, *(s++));
+					}
+				} else if (s[0] == '*') {
+					size_t depth = 1;
+					while (depth) {
+						consume(&pos, *(s++));
+						if (s[0] == '/') {
+							consume(&pos, *(s++));
+							if (s[0] == '*')
+								depth++;
+						} else if (s[0] == '*') {
+							consume(&pos, *(s++));
+							if (s[0] == '/')
+								depth--;
+						} else if (s[0] == 0) {
+							set_err("Unclosed comment");
+							return toks;
+						}
+					}
+					consume(&pos, *(s++));
+				} else {
+					emit(&toks, &pos, (Tok){
+							.kind = TokOp,
+							.Op = '/',
+						});
+				}
+				continue;
+			default:
+				set_err("Unrecognized character: '%c'", s[0]);
+				return toks;
+		}
+		consume(&pos, *(s++));
+	}
+end_of_file:
+	emit(&toks, &pos, (Tok){
+			.kind = TokOp,
+			.Op = OpEOF,
+		});
+	return toks;
+}