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Chapter 17.5 - 17.6

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Tom Willemse 2021-08-17 20:41:54 -07:00
parent 0b89bd5de0
commit 964859a8a1
Signed by: ryuslash
GPG key ID: 7D5C407B435025C1
1 changed files with 96 additions and 2 deletions
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98
clox/src/compiler.c
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@ -26,6 +26,14 @@ typedef enum {
PREC_PRIMARY
} Precedence;
typedef void (*ParseFn)();
typedef struct {
ParseFn prefix;
ParseFn infix;
Precedence precedence;
} ParseRule;
Parser parser;
Chunk *compilingChunk;
@ -103,9 +111,33 @@ static void emitConstant(Value value) {
static void endCompiler() { emitReturn(); }
static void parsePrecedence(Precedence precedence) {
// What goes here?
static void expression();
static ParseRule *getRule(TokenType type);
static void parsePrecedence(Precedence precedence);
static void binary() {
TokenType operatorType = parser.previous.type;
ParseRule *rule = getRule(operatorType);
parsePrecedence((Precedence)(rule->precedence + 1));
switch (operatorType) {
case TOKEN_PLUS:
emitByte(OP_ADD);
break;
case TOKEN_MINUS:
emitByte(OP_SUBTRACT);
break;
case TOKEN_STAR:
emitByte(OP_MULTIPLY);
break;
case TOKEN_SLASH:
emitByte(OP_DIVIDE);
break;
default:
return; // Unreachable.
}
}
static void expression() { parsePrecedence(PREC_ASSIGNMENT); }
static void number() {
@ -134,6 +166,68 @@ static void grouping() {
consume(TOKEN_RIGHT_PAREN, "Expect ')' after expression.");
}
ParseRule rules[] = {
[TOKEN_LEFT_PAREN] = {grouping, NULL, PREC_NONE},
[TOKEN_RIGHT_PAREN] = {NULL, NULL, PREC_NONE},
[TOKEN_LEFT_BRACE] = {NULL, NULL, PREC_NONE},
[TOKEN_RIGHT_BRACE] = {NULL, NULL, PREC_NONE},
[TOKEN_COMMA] = {NULL, NULL, PREC_NONE},
[TOKEN_DOT] = {NULL, NULL, PREC_NONE},
[TOKEN_MINUS] = {unary, binary, PREC_TERM},
[TOKEN_PLUS] = {NULL, binary, PREC_TERM},
[TOKEN_SEMICOLON] = {NULL, NULL, PREC_NONE},
[TOKEN_SLASH] = {NULL, binary, PREC_FACTOR},
[TOKEN_STAR] = {NULL, binary, PREC_FACTOR},
[TOKEN_BANG] = {NULL, NULL, PREC_NONE},
[TOKEN_BANG_EQUAL] = {NULL, NULL, PREC_NONE},
[TOKEN_EQUAL] = {NULL, NULL, PREC_NONE},
[TOKEN_EQUAL_EQUAL] = {NULL, NULL, PREC_NONE},
[TOKEN_GREATER] = {NULL, NULL, PREC_NONE},
[TOKEN_GREATER_EQUAL] = {NULL, NULL, PREC_NONE},
[TOKEN_LESS] = {NULL, NULL, PREC_NONE},
[TOKEN_LESS_EQUAL] = {NULL, NULL, PREC_NONE},
[TOKEN_IDENTIFIER] = {NULL, NULL, PREC_NONE},
[TOKEN_STRING] = {NULL, NULL, PREC_NONE},
[TOKEN_NUMBER] = {number, NULL, PREC_NONE},
[TOKEN_AND] = {NULL, NULL, PREC_NONE},
[TOKEN_CLASS] = {NULL, NULL, PREC_NONE},
[TOKEN_ELSE] = {NULL, NULL, PREC_NONE},
[TOKEN_FALSE] = {NULL, NULL, PREC_NONE},
[TOKEN_FOR] = {NULL, NULL, PREC_NONE},
[TOKEN_FUN] = {NULL, NULL, PREC_NONE},
[TOKEN_IF] = {NULL, NULL, PREC_NONE},
[TOKEN_NIL] = {NULL, NULL, PREC_NONE},
[TOKEN_OR] = {NULL, NULL, PREC_NONE},
[TOKEN_PRINT] = {NULL, NULL, PREC_NONE},
[TOKEN_RETURN] = {NULL, NULL, PREC_NONE},
[TOKEN_SUPER] = {NULL, NULL, PREC_NONE},
[TOKEN_THIS] = {NULL, NULL, PREC_NONE},
[TOKEN_TRUE] = {NULL, NULL, PREC_NONE},
[TOKEN_VAR] = {NULL, NULL, PREC_NONE},
[TOKEN_WHILE] = {NULL, NULL, PREC_NONE},
[TOKEN_ERROR] = {NULL, NULL, PREC_NONE},
[TOKEN_EOF] = {NULL, NULL, PREC_NONE},
};
static void parsePrecedence(Precedence precedence) {
advance();
ParseFn prefixRule = getRule(parser.previous.type)->prefix;
if (prefixRule == NULL) {
error("Expect expression.");
return;
}
prefixRule();
while (precedence <= getRule(parser.current.type)->precedence) {
advance();
ParseFn infixRule = getRule(parser.previous.type)->infix;
infixRule();
}
}
static ParseRule *getRule(TokenType type) { return &rules[type]; }
bool compile(const char *source, Chunk *chunk) {
initScanner(source);
compilingChunk = chunk;