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compiler.c
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compiler.c
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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "compiler.h"
#include "disasm.h"
#include "memory.h"
#include "scanner.h"
typedef struct {
Token current;
Token previous;
bool hadError;
bool panicMode;
} Parser;
typedef enum {
PREC_NONE,
PREC_ASSIGNMENT, // =
PREC_OR, // or
PREC_AND, // and
PREC_EQUALITY, // == !=
PREC_COMPARISON, // < > <= >=
PREC_TERM, // + -
PREC_FACTOR, // * \ /
PREC_UNARY, // ! -
PREC_POSTFIX // . () [] @ ^
} Precedence;
typedef void (*ParseFn)(bool canAssign);
typedef struct {
ParseFn prefix;
ParseFn infix;
Precedence precedence;
} ParseRule;
typedef struct {
Token name;
int8_t depth;
uint8_t isCaptured;
int16_t _dummy; // force size 16 to avoid multiplication in offset calculation
} Local;
typedef enum {
TYPE_FUN,
TYPE_INIT,
TYPE_METHOD,
TYPE_SCRIPT,
TYPE_LAMBDA
} FunctionType;
typedef struct LoopInfo {
struct LoopInfo* enclosing;
int8_t scopeDepth;
int8_t breakCount;
int16_t breaks[MAX_BREAKS];
} LoopInfo;
typedef struct Compiler {
struct Compiler* enclosing;
ObjFunction* target;
FunctionType type;
Local locals[MAX_LOCALS];
Upvalue upvalues[MAX_UPVALUES];
int8_t scopeDepth;
uint8_t localCount;
LoopInfo* currentLoop;
} Compiler;
typedef struct ClassCompiler {
struct ClassCompiler* enclosing;
bool hasSuperclass;
} ClassCompiler;
static Parser parser;
static Compiler* currentComp;
static ClassCompiler* currentClass;
static Chunk* currentChunk(void) {
return ¤tComp->target->chunk;
}
////////////////////////////////////////////////////////////////////////////////////////////////////
// Error reporting
////////////////////////////////////////////////////////////////////////////////////////////////////
static void errorAt(Token* token, const char* message) {
if (parser.panicMode)
return;
parser.panicMode = true;
printf("[line %d] Error", token->line);
if (token->type == TOKEN_EOF)
putstr(" at end");
else if (token->type != TOKEN_ERROR) {
// IDE68K's printf("%.*s") is broken
putstr(" at '");
putstrn(token->length, token->start);
putstr("'");
}
printf(": %s\n", message);
parser.hadError = true;
}
static void error(const char* message) {
errorAt(&parser.previous, message);
}
static void errorAtCurrent(const char* message) {
errorAt(&parser.current, message);
}
////////////////////////////////////////////////////////////////////////////////////////////////////
// Token matching
////////////////////////////////////////////////////////////////////////////////////////////////////
static void advance(void) {
parser.previous = parser.current;
for (;;) {
parser.current = scanToken();
if (parser.current.type != TOKEN_ERROR)
break;
errorAtCurrent(parser.current.start);
}
}
static void consume(TokenType type, const char* message) {
if (parser.current.type == type) {
advance();
return;
}
errorAtCurrent(message);
}
static void consumeExp(TokenType expected, const char* context) {
if (parser.current.type == expected) {
advance();
return;
}
sprintf(buffer, "Expect '%c' %s %s.",
TOKEN_CHARS[expected],
expected == TOKEN_LEFT_BRACE || expected == TOKEN_LEFT_PAREN ? "before" : "after",
context);
errorAtCurrent(buffer);
}
static bool check(TokenType type) {
return parser.current.type == type;
}
static bool match(TokenType type) {
if (parser.current.type != type)
return false;
advance();
return true;
}
static void synchronize(void) {
parser.panicMode = false;
while (parser.current.type != TOKEN_EOF) {
if (parser.previous.type == TOKEN_SEMICOLON) return;
// Original switch crashed the compiler, no idea, why....
if (parser.current.type == TOKEN_CLASS) return;
if (parser.current.type == TOKEN_FUN) return;
if (parser.current.type == TOKEN_VAR) return;
if (parser.current.type == TOKEN_FOR) return;
if (parser.current.type == TOKEN_IF) return;
if (parser.current.type == TOKEN_WHILE) return;
if (parser.current.type == TOKEN_PRINT) return;
if (parser.current.type == TOKEN_RETURN) return;
if (parser.current.type == TOKEN_CASE) return;
advance();
}
}
////////////////////////////////////////////////////////////////////////////////////////////////////
// Code emitting
////////////////////////////////////////////////////////////////////////////////////////////////////
static void emitByte(int byte) {
writeChunk(currentChunk(), byte, parser.previous.line);
}
static void emit2Bytes(int byte1, int byte2) {
emitByte(byte1);
emitByte(byte2);
}
static void emit3Bytes(int byte1, int byte2, int byte3) {
emitByte(byte1);
emitByte(byte2);
emitByte(byte3);
}
static void emitLoop(int loopStart) {
int offset;
emitByte(OP_LOOP);
offset = currentChunk()->count - loopStart + 2;
if (offset > UINT16_MAX)
error("Jump too large.");
emit2Bytes(offset >> 8, offset);
}
static int emitJump(int instruction) {
emit3Bytes(instruction, 0xff, 0xff);
return currentChunk()->count - 2;
}
static void emitReturn(void) {
if (currentComp->type == TYPE_INIT)
emit3Bytes(OP_GET_LOCAL, 0, OP_RETURN);
else
emitByte(OP_RETURN_NIL);
}
static int makeConstant(Value value) {
int constant = addConstant(currentChunk(), value);
if (constant > UINT8_MAX) {
error("Too many constants in one chunk.");
return 0;
}
return constant;
}
static void emitConstant(Value value) {
if (value == INT_VAL(0)) emitByte(OP_ZERO);
else if (value == INT_VAL(1)) emitByte(OP_ONE);
else emit2Bytes(OP_CONSTANT, makeConstant(value));
}
static void patchJump(int offset) {
// -2 to adjust for the bytecode for the jump offset itself.
int jump = currentChunk()->count - offset - 2;
if (jump > UINT16_MAX)
error("Jump too large.");
currentChunk()->code[offset] = jump >> 8;
currentChunk()->code[offset + 1] = jump;
}
////////////////////////////////////////////////////////////////////////////////////////////////////
// Compiler scoping
////////////////////////////////////////////////////////////////////////////////////////////////////
static void initCompiler(Compiler* compiler, FunctionType type) {
Local* local;
compiler->enclosing = currentComp;
compiler->target = NULL;
compiler->type = type;
compiler->localCount = 0;
compiler->scopeDepth = 0;
compiler->target = makeFunction();
compiler->currentLoop = NULL;
currentComp = compiler;
if (type != TYPE_SCRIPT) {
if (type == TYPE_LAMBDA)
currentComp->target->name = INT_VAL(vm.lambdaCount++);
else
currentComp->target->name =
OBJ_VAL(makeString(parser.previous.start, parser.previous.length));
}
local = ¤tComp->locals[currentComp->localCount++];
local->depth = 0;
local->isCaptured = false;
if (type == TYPE_METHOD || type == TYPE_INIT) {
local->name.start = "this";
local->name.length = 4;
} else {
local->name.start = "";
local->name.length = 0;
}
}
static ObjFunction* endCompiler(bool addReturn) {
ObjFunction* function = currentComp->target;
if (addReturn)
emitReturn();
freezeChunk(currentChunk());
if (vm.debug_print_code && !parser.hadError)
disassembleChunk(currentChunk(), functionName(function));
currentComp = currentComp->enclosing;
return function;
}
static void beginScope(void) {
currentComp->scopeDepth++;
}
static void endScope(void) {
currentComp->scopeDepth--;
while (currentComp->localCount > 0 &&
currentComp->locals[currentComp->localCount - 1].depth > currentComp->scopeDepth) {
if (currentComp->locals[currentComp->localCount - 1].isCaptured)
emitByte(OP_CLOSE_UPVALUE);
else
emitByte(OP_POP);
currentComp->localCount--;
}
}
////////////////////////////////////////////////////////////////////////////////////////////////////
// Forward declarations
////////////////////////////////////////////////////////////////////////////////////////////////////
static void expression(void);
static void statement(void);
static void declaration(void);
static void function(FunctionType type);
static void parsePrecedence(Precedence precedence);
static int argumentList(bool* isVarArg, TokenType terminator);
static int identifierConstant(Token* name);
static const ParseRule* getRule(TokenType type);
////////////////////////////////////////////////////////////////////////////////////////////////////
// Expressions
////////////////////////////////////////////////////////////////////////////////////////////////////
static void binary(bool canAssign) {
TokenType operatorType = parser.previous.type;
const ParseRule* rule = getRule(operatorType);
parsePrecedence((Precedence)(rule->precedence + 1));
switch (operatorType) {
case TOKEN_BANG_EQUAL: emit2Bytes(OP_EQUAL, OP_NOT); break;
case TOKEN_EQUAL_EQUAL: emitByte(OP_EQUAL); break;
case TOKEN_GREATER: emit2Bytes(OP_SWAP, OP_LESS); break;
case TOKEN_LESS_EQUAL: emit3Bytes(OP_SWAP, OP_LESS, OP_NOT); break;
case TOKEN_LESS: emitByte(OP_LESS); break;
case TOKEN_GREATER_EQUAL: emit2Bytes(OP_LESS, OP_NOT); break;
case TOKEN_PLUS: emitByte(OP_ADD); break;
case TOKEN_MINUS: emitByte(OP_SUB); break;
case TOKEN_STAR: emitByte(OP_MUL); break;
case TOKEN_SLASH: emitByte(OP_DIV); break;
case TOKEN_BACKSLASH: emitByte(OP_MOD); break;
default: return; // Unreachable
}
}
static void call(bool canAssign) {
bool isVarArg = false;
int argCount = argumentList(&isVarArg, TOKEN_RIGHT_PAREN);
if (isVarArg)
emit2Bytes(OP_VCALL, argCount);
else if (argCount <= 2)
emitByte(OP_CALL0 + argCount); // special case 0, 1, or 2 args
else
emit2Bytes(OP_CALL, argCount);
}
static void dot(bool canAssign) {
int pname;
int argCount;
bool isVarArg = false;
consume(TOKEN_IDENTIFIER, "Expect property name after '.'.");
pname = identifierConstant(&parser.previous);
if (canAssign && match(TOKEN_EQUAL)) {
expression();
emit2Bytes(OP_SET_PROPERTY, pname);
} else if (match(TOKEN_LEFT_PAREN)) {
argCount = argumentList(&isVarArg, TOKEN_RIGHT_PAREN);
emit3Bytes(isVarArg ? OP_VINVOKE : OP_INVOKE, pname, argCount);
} else
emit2Bytes(OP_GET_PROPERTY, pname);
}
static void slice(bool canAssign) {
if (match(TOKEN_RIGHT_BRACKET))
emitConstant(INT_VAL(INT32_MAX>>1));
else {
expression();
consumeExp(TOKEN_RIGHT_BRACKET, "slice");
}
if (canAssign && match(TOKEN_EQUAL)) {
error("Invalid assignment target.");
return;
} else
emitByte(OP_GET_SLICE);
}
static void index_(bool canAssign) {
if (match(TOKEN_COLON)) {
emitConstant(INT_VAL(0));
slice(canAssign);
} else {
expression();
if (match(TOKEN_COLON))
slice(canAssign);
else {
consumeExp(TOKEN_RIGHT_BRACKET, "index");
if (canAssign && match(TOKEN_EQUAL)) {
expression();
emitByte(OP_SET_INDEX);
} else
emitByte(OP_GET_INDEX);
}
}
}
static void iter(bool canAssign) {
TokenType accessor = parser.previous.type;
if (canAssign && match(TOKEN_EQUAL)) {
if (accessor == TOKEN_HAT) {
expression();
emitByte(OP_SET_ITVAL);
} else
error("Invalid assignment target.");
} else
emitByte(accessor == TOKEN_HAT ? OP_GET_ITVAL : OP_GET_ITKEY);
}
static void literal(bool canAssign) {
switch (parser.previous.type) {
case TOKEN_FALSE: emitByte(OP_FALSE); break;
case TOKEN_NIL: emitByte(OP_NIL); break;
case TOKEN_TRUE: emitByte(OP_TRUE); break;
default: return; // unreachable
}
}
static void grouping(bool canAssign) {
expression();
consumeExp(TOKEN_RIGHT_PAREN, "expression");
}
static void intNum(bool canAssign) {
Value value = parseInt(parser.previous.start, false);
emitConstant(value);
}
static void realNum(bool canAssign) {
Value value;
errno = 0;
value = makeReal(strToReal(parser.previous.start, NULL));
if (errno != 0)
error("Real constant overflow.");
emitConstant(value);
}
static void string(bool canAssign) {
// Redundant code in IDE68K without str local variable?
ObjString* str = makeString(parser.previous.start + 1, parser.previous.length - 2);
emitConstant(OBJ_VAL(str));
}
static int identifierConstant(Token* name) {
// Redundant code in IDE68K without str local variable?
ObjString* str = makeString(name->start, name->length);
return makeConstant(OBJ_VAL(str));
}
static void list(bool canAssign) {
bool isVarArg = false;
int argCount = argumentList(&isVarArg, TOKEN_RIGHT_BRACKET);
emit2Bytes(isVarArg ? OP_VLIST : OP_LIST, argCount);
}
////////////////////////////////////////////////////////////////////////////////////////////////////
// Variable handling
////////////////////////////////////////////////////////////////////////////////////////////////////
static bool identifiersEqual(Token* a, Token* b) {
if (a->length != b->length)
return false;
return fix_memcmp(a->start, b->start, a->length) == 0;
}
static int resolveLocal(Compiler* compiler, Token* name) {
int i;
Local* local;
for (i = compiler->localCount - 1; i >= 0; i--) {
local = &compiler->locals[i];
if (identifiersEqual(name, &local->name)) {
if (local->depth == -1)
error("Can't read local variable in its own initializer.");
return i;
}
}
return -1;
}
static int addUpvalue(Compiler* compiler, int index, bool isLocal) {
int upvalueCount = compiler->target->upvalueCount;
Upvalue newUpvalue = isLocal ? (index | LOCAL_MASK) : index;
int i;
for (i = 0; i < upvalueCount; i++)
if (compiler->upvalues[i] == newUpvalue)
return i;
if (upvalueCount == MAX_UPVALUES) {
error("Too many upvalues in function.");
return 0;
}
compiler->upvalues[upvalueCount] = newUpvalue;
return compiler->target->upvalueCount++;
}
static int resolveUpvalue(Compiler* compiler, Token* name) {
int local, upvalue;
if (compiler->enclosing == NULL)
return -1;
local = resolveLocal(compiler->enclosing, name);
if (local != -1) {
compiler->enclosing->locals[local].isCaptured = true;
return addUpvalue(compiler, local, true);
}
upvalue = resolveUpvalue(compiler->enclosing, name);
if (upvalue != -1)
return addUpvalue(compiler, upvalue, false);
return -1;
}
static void addLocal(Token name) {
Local* local;
if (currentComp->localCount == MAX_LOCALS) {
error("Too many local variables in function.");
return;
}
local = ¤tComp->locals[currentComp->localCount++];
local->name = name;
local->depth = -1;
local->isCaptured = false;
}
static void declareVariable(void) {
Token* name;
int i;
Local* local;
if (currentComp->scopeDepth == 0)
return;
name = &parser.previous;
for (i = currentComp->localCount - 1; i >= 0; i--) {
local = ¤tComp->locals[i];
if (local->depth != -1 && local->depth < currentComp->scopeDepth)
break;
if (identifiersEqual(name, &local->name))
error("Already a variable with this name in this scope.");
}
addLocal(*name);
}
static void namedVariable(Token name, bool canAssign) {
int getOp, setOp;
int arg = resolveLocal(currentComp, &name);
if (arg != -1) {
getOp = OP_GET_LOCAL;
setOp = OP_SET_LOCAL;
} else if ((arg = resolveUpvalue(currentComp, &name)) != -1) {
getOp = OP_GET_UPVALUE;
setOp = OP_SET_UPVALUE;
} else {
arg = identifierConstant(&name);
getOp = OP_GET_GLOBAL;
setOp = OP_SET_GLOBAL;
}
if (canAssign && match(TOKEN_EQUAL)) {
expression();
emit2Bytes(setOp, arg);
} else
emit2Bytes(getOp, arg);
}
static void variable(bool canAssign) {
namedVariable(parser.previous, canAssign);
}
////////////////////////////////////////////////////////////////////////////////////////////////////
// Expressions continued
////////////////////////////////////////////////////////////////////////////////////////////////////
static Token syntheticToken(const char* text) {
Token token;
token.start = text;
token.length = (int)strlen(text);
return token;
}
static void super_(bool canAssign) {
int mname;
int argCount;
bool isVarArg = false;
if (currentClass == NULL)
error("Can't use 'super' outside of a class.");
else if (!currentClass->hasSuperclass)
error("Can't use 'super' in a class with no superclass.");
consumeExp(TOKEN_DOT, "'super'");
consume(TOKEN_IDENTIFIER, "Expect superclass method name.");
mname = identifierConstant(&parser.previous);
namedVariable(syntheticToken("this"), false);
if (match(TOKEN_LEFT_PAREN)) {
argCount = argumentList(&isVarArg, TOKEN_RIGHT_PAREN);
namedVariable(syntheticToken("super"), false);
emit3Bytes(isVarArg ? OP_VSUPER_INVOKE : OP_SUPER_INVOKE, mname, argCount);
} else {
namedVariable(syntheticToken("super"), false);
emit2Bytes(OP_GET_SUPER, mname);
}
}
static void this_(bool canAssign) {
if (currentClass == NULL) {
error("Can't use 'this' outside of a class.");
return;
}
variable(false);
}
static void and_(bool canAssign) {
int endJump = emitJump(OP_JUMP_AND);
parsePrecedence(PREC_AND);
patchJump(endJump);
}
static void or_(bool canAssign) {
int endJump = emitJump(OP_JUMP_OR);
parsePrecedence(PREC_OR);
patchJump(endJump);
}
static void unary(bool canAssign) {
switch (parser.previous.type) {
case TOKEN_BANG:
parsePrecedence(PREC_UNARY);
emitByte(OP_NOT);
break;
case TOKEN_MINUS:
emitConstant(INT_VAL(0));
parsePrecedence(PREC_UNARY);
emitByte(OP_SUB);
break;
default: return; // Unreachable
}
}
static void lambda(bool canAssign) {
function(TYPE_LAMBDA);
}
static void handler(bool canAssign) {
Compiler compiler;
ObjFunction* function;
int i;
consumeExp(TOKEN_LEFT_PAREN, "thunk");
// Build a thunk around expression
initCompiler(&compiler, TYPE_LAMBDA);
beginScope();
expression();
emitByte(OP_RETURN);
function = endCompiler(false);
emit2Bytes(OP_CLOSURE, makeConstant(OBJ_VAL(function)));
for (i = 0; i < function->upvalueCount; i++)
emitByte(compiler.upvalues[i]);
consumeExp(TOKEN_COLON, "thunk");
expression();
consumeExp(TOKEN_RIGHT_PAREN, "handler");
emitByte(OP_CALL_HAND);
}
static void ifExpr(bool canAssign) {
int thenJump, elseJump;
consumeExp(TOKEN_LEFT_PAREN, "condition");
expression();
consumeExp(TOKEN_COLON, "condition");
thenJump = emitJump(OP_JUMP_FALSE);
expression();
consumeExp(TOKEN_COLON, "consequent");
elseJump = emitJump(OP_JUMP);
patchJump(thenJump);
expression();
patchJump(elseJump);
consumeExp(TOKEN_RIGHT_PAREN, "alternative");
}
static const ParseRule rules[] = {
// Keep same order as TokenType enum values in scanner.h
// since C89 doesn't support array init by index values.
// single character punctuation ***********************************
/* [TOKEN_LEFT_PAREN] = */ {grouping, call, PREC_POSTFIX},
/* [TOKEN_RIGHT_PAREN] = */ {NULL, NULL, PREC_NONE},
/* [TOKEN_LEFT_BRACE] = */ {NULL, NULL, PREC_NONE},
/* [TOKEN_RIGHT_BRACE] = */ {NULL, NULL, PREC_NONE},
/* [TOKEN_LEFT_BRACKET] = */ {list, index_, PREC_POSTFIX},
/* [TOKEN_RIGHT_BRACKET] = */ {NULL, NULL, PREC_NONE},
/* [TOKEN_COMMA] = */ {NULL, NULL, PREC_NONE},
/* [TOKEN_DOT] = */ {NULL, dot, PREC_POSTFIX},
/* [TOKEN_SEMICOLON] = */ {NULL, NULL, PREC_NONE},
/* [TOKEN_COLON] = */ {NULL, NULL, PREC_NONE},
// single character operators *************************************
/* [TOKEN_PLUS] = */ {NULL, binary, PREC_TERM},
/* [TOKEN_MINUS] = */ {unary, binary, PREC_TERM},
/* [TOKEN_STAR] = */ {NULL, binary, PREC_FACTOR},
/* [TOKEN_SLASH] = */ {NULL, binary, PREC_FACTOR},
/* [TOKEN_BACKSLASH] = */ {NULL, binary, PREC_FACTOR},
/* [TOKEN_AT] = */ {NULL, iter, PREC_POSTFIX},
/* [TOKEN_HAT] = */ {NULL, iter, PREC_POSTFIX},
/* [TOKEN_BANG] = */ {unary, NULL, PREC_NONE},
/* [TOKEN_EQUAL] = */ {NULL, NULL, PREC_NONE},
/* [TOKEN_GREATER] = */ {NULL, binary, PREC_COMPARISON},
/* [TOKEN_LESS] = */ {NULL, binary, PREC_COMPARISON},
// double character operators *************************************
/* [TOKEN_BANG_EQUAL] = */ {NULL, binary, PREC_EQUALITY},
/* [TOKEN_EQUAL_EQUAL] = */ {NULL, binary, PREC_EQUALITY},
/* [TOKEN_GREATER_EQUAL] = */ {NULL, binary, PREC_COMPARISON},
/* [TOKEN_LESS_EQUAL] = */ {NULL, binary, PREC_COMPARISON},
/* [TOKEN_DOT_DOT] = */ {NULL, NULL, PREC_NONE},
/* [TOKEN_ARROW] = */ {NULL, NULL, PREC_NONE},
// literals *******************************************************
/* [TOKEN_IDENTIFIER] = */ {variable, NULL, PREC_NONE},
/* [TOKEN_STRING] = */ {string, NULL, PREC_NONE},
/* [TOKEN_INT] = */ {intNum, NULL, PREC_NONE},
/* [TOKEN_REAL] = */ {realNum, NULL, PREC_NONE},
// keywords *******************************************************
/* [TOKEN_AND] = */ {NULL, and_, PREC_AND},
/* [TOKEN_BREAK] = */ {NULL, NULL, PREC_NONE},
/* [TOKEN_CASE] = */ {NULL, NULL, PREC_NONE},
/* [TOKEN_CLASS] = */ {NULL, NULL, PREC_NONE},
/* [TOKEN_ELSE] = */ {NULL, NULL, PREC_NONE},
/* [TOKEN_FALSE] = */ {literal, NULL, PREC_NONE},
/* [TOKEN_FOR] = */ {NULL, NULL, PREC_NONE},
/* [TOKEN_FUN] = */ {lambda, NULL, PREC_NONE},
/* [TOKEN_HANDLE] = */ {handler, NULL, PREC_NONE},
/* [TOKEN_IF] = */ {ifExpr, NULL, PREC_NONE},
/* [TOKEN_NIL] = */ {literal, NULL, PREC_NONE},
/* [TOKEN_OR] = */ {NULL, or_, PREC_OR},
/* [TOKEN_PRINT] = */ {NULL, NULL, PREC_NONE},
/* [TOKEN_RETURN] = */ {NULL, NULL, PREC_NONE},
/* [TOKEN_SUPER] = */ {super_, NULL, PREC_NONE},
/* [TOKEN_THIS] = */ {this_, NULL, PREC_NONE},
/* [TOKEN_TRUE] = */ {literal, NULL, PREC_NONE},
/* [TOKEN_VAR] = */ {NULL, NULL, PREC_NONE},
/* [TOKEN_WHEN] = */ {NULL, NULL, PREC_NONE},
/* [TOKEN_WHILE] = */ {NULL, NULL, PREC_NONE},
// specials *******************************************************
/* [TOKEN_ERROR] = */ {NULL, NULL, PREC_NONE},
/* [TOKEN_EOF] = */ {NULL, NULL, PREC_NONE},
};
static void parsePrecedence(Precedence precedence) {
ParseFn prefixRule;
ParseFn infixRule;
bool canAssign;
advance();
prefixRule = getRule(parser.previous.type)->prefix;
if (prefixRule == NULL) {
error("Expect expression.");
return;
}
canAssign = precedence <= PREC_ASSIGNMENT;
(*prefixRule)(canAssign);
while (precedence <= getRule(parser.current.type)->precedence) {
advance();
infixRule = getRule(parser.previous.type)->infix;
(*infixRule)(canAssign);
}
if (canAssign && match(TOKEN_EQUAL))
error("Invalid assignment target.");
}
static int parseVariable(const char* errorMessage) {
consume(TOKEN_IDENTIFIER, errorMessage);
declareVariable();
if (currentComp->scopeDepth > 0)
return 0;
return identifierConstant(&parser.previous);
}
static void markInitialized(void) {
if (currentComp->scopeDepth == 0)
return;
currentComp->locals[currentComp->localCount - 1].depth = currentComp->scopeDepth;
}
static void defineVariable(int global) {
if (currentComp->scopeDepth > 0) {
markInitialized();
return;
}
emit2Bytes(OP_DEF_GLOBAL, global);
}
static int argumentList(bool* isVarArg, TokenType terminator) {
int argCount = 0;
if (!check(terminator)) {
do {
if (match(TOKEN_DOT_DOT)) {
// First UNPACK, introduce count of arguments from lists
if (!*isVarArg)
emitConstant(INT_VAL(0));
*isVarArg = true;
expression();
emitByte(OP_UNPACK); // this also adapts list arguments count
} else {
expression();
if (*isVarArg)
emitByte(OP_SWAP); // bubble list arguments count to TOS
if (argCount == UINT8_MAX)
error("Too many arguments.");
argCount++;
}
} while (match(TOKEN_COMMA));
}
consumeExp(terminator, "arguments");
return argCount;
}
static const ParseRule* getRule(TokenType type) {
return &rules[type];
}
static void expression(void) {
CHECK_STACKOVERFLOW
parsePrecedence(PREC_ASSIGNMENT);
}
static void block(void) {
while (!check(TOKEN_RIGHT_BRACE) && !check(TOKEN_EOF))
declaration();
consumeExp(TOKEN_RIGHT_BRACE, "block");
}
static void function(FunctionType type) {
Compiler compiler;
ObjFunction* function;
int i;
int parameter;
uint8_t restParm = 0;
CHECK_STACKOVERFLOW
initCompiler(&compiler, type);
beginScope();
consumeExp(TOKEN_LEFT_PAREN, "parameters");
if (!check(TOKEN_RIGHT_PAREN)) {
do {
if (restParm)
errorAtCurrent("No more parameters allowed after rest parameter.");
if (++currentComp->target->arity >= MAX_LOCALS)
errorAtCurrent("Too many parameters.");
if (match(TOKEN_DOT_DOT))
restParm = REST_PARM_MASK;
parameter = parseVariable("Expect parameter name.");
defineVariable(parameter);
} while (match(TOKEN_COMMA));
}
consumeExp(TOKEN_RIGHT_PAREN, "parameters");
currentComp->target->arity |= restParm;
if (match(TOKEN_ARROW)) {
if (type == TYPE_INIT)
error("Can't return a value from an initializer.");
expression();
emitByte(OP_RETURN);
function = endCompiler(false);
} else {
consumeExp(TOKEN_LEFT_BRACE, "function body");
block();
function = endCompiler(true);
}
emit2Bytes(OP_CLOSURE, makeConstant(OBJ_VAL(function)));
for (i = 0; i < function->upvalueCount; i++)
emitByte(compiler.upvalues[i]);
}
static void method(void) {
int mname;
FunctionType type = TYPE_METHOD;
consume(TOKEN_IDENTIFIER, "Expect method name.");
mname = identifierConstant(&parser.previous);
if (parser.previous.length == 4 && fix_memcmp(parser.previous.start, "init", 4) == 0)
type = TYPE_INIT;
function(type);
emit2Bytes(OP_METHOD, mname);
}
////////////////////////////////////////////////////////////////////////////////////////////////////
// Declarations
////////////////////////////////////////////////////////////////////////////////////////////////////
static void classDeclaration(void) {
int nameConstant;
Token className;
ClassCompiler classCompiler;
consume(TOKEN_IDENTIFIER, "Expect class name.");
className = parser.previous;
nameConstant = identifierConstant(&className);
declareVariable();
emit2Bytes(OP_CLASS, nameConstant);
defineVariable(nameConstant);
classCompiler.enclosing = currentClass;
classCompiler.hasSuperclass = false;
currentClass = &classCompiler;
if (match(TOKEN_LESS)) {
// superclass can be any expression!
expression();
beginScope();
addLocal(syntheticToken("super"));
defineVariable(0);
namedVariable(className, false);
emitByte(OP_INHERIT);
classCompiler.hasSuperclass = true;
}
namedVariable(className, false);
consumeExp(TOKEN_LEFT_BRACE, "class body");
while (!check(TOKEN_RIGHT_BRACE) && !check(TOKEN_EOF))
method();
consumeExp(TOKEN_RIGHT_BRACE, "class body");
emitByte(OP_POP);
if (classCompiler.hasSuperclass)
endScope();
currentClass = currentClass->enclosing;
}
static void funDeclaration(void) {
int fname = parseVariable("Expect function name.");
markInitialized();
function(TYPE_FUN);
defineVariable(fname);
}
static void varDeclaration(void) {
int vname;
do {
vname = parseVariable("Expect variable name.");
if (match(TOKEN_EQUAL))
expression();
else
emitByte(OP_NIL);
defineVariable(vname);
} while (match(TOKEN_COMMA));
consumeExp(TOKEN_SEMICOLON, "variable declarations");
}
////////////////////////////////////////////////////////////////////////////////////////////////////
// Statements
////////////////////////////////////////////////////////////////////////////////////////////////////
static void expressionStatement(void) {
expression();
consumeExp(TOKEN_SEMICOLON, "expression");
emitByte(OP_POP);
}