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added multiple return value support to the parser

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CPunch
2020-12-14 14:38:46 -06:00
parent 48ceca1834
commit 4f3f594b82
3 changed files with 84 additions and 45 deletions
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104
src/cparse.c
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@@ -36,6 +36,7 @@ typedef struct CCompilerState {
int scopeDepth;
int pushedValues;
int savedPushed;
int expectedValues;
struct CCompilerState* enclosing;
} CCompilerState;
@@ -75,7 +76,7 @@ typedef struct {
static void parsePrecedence(CParseState*, Precedence);
static void variable(CParseState *pstate, bool canAssign);
static void expression(CParseState*);
static int expression(CParseState *pstate, int needed, bool forceNeeded);
static void statement(CParseState *pstate);
static void declaration(CParseState *pstate);
static void function(CParseState *pstate, FunctionType type);
@@ -94,6 +95,7 @@ static void initCompilerState(CParseState* pstate, CCompilerState *ccstate, Func
ccstate->scopeDepth = 0;
ccstate->pushedValues = 0;
ccstate->savedPushed = 0;
ccstate->expectedValues = 0;
ccstate->type = type;
ccstate->function = cosmoO_newFunction(pstate->state);
ccstate->function->module = pstate->module;
@@ -340,7 +342,7 @@ static int parseArguments(CParseState *pstate) {
// there are args to parse!
if (!check(pstate, TOKEN_RIGHT_PAREN)) {
do {
expression(pstate);
expression(pstate, 1, true);
args++;
} while(match(pstate, TOKEN_COMMA));
}
@@ -434,7 +436,7 @@ static void binary(CParseState *pstate, bool canAssign) {
}
static void group(CParseState *pstate, bool canAssign) {
expression(pstate);
expression(pstate, 1, true);
consume(pstate, TOKEN_RIGHT_PAREN, "Expected ')'");
}
@@ -469,7 +471,7 @@ static void namedVariable(CParseState *pstate, CToken name, bool canAssign, bool
if (canAssign && match(pstate, TOKEN_EQUAL)) {
// setter
expression(pstate);
expression(pstate, 1, true);
_etterOP(pstate, opSet, arg);
valuePopped(pstate, 1);
} else if (canIncrement && match(pstate, TOKEN_PLUS_PLUS)) { // i++
@@ -549,8 +551,8 @@ static void call_(CParseState *pstate, bool canAssign) {
valuePopped(pstate, argCount + 1); // all of these values will be popped off the stack when returned (+1 for the function)
writeu8(pstate, OP_CALL);
writeu8(pstate, argCount);
writeu8(pstate, 1); // TODO
valuePushed(pstate, 1);
writeu8(pstate, pstate->compiler->expectedValues); // TODO
valuePushed(pstate, pstate->compiler->expectedValues);
}
static void object(CParseState *pstate, bool canAssign) {
@@ -560,12 +562,12 @@ static void object(CParseState *pstate, bool canAssign) {
if (!match(pstate, TOKEN_RIGHT_BRACE)) {
do {
// parse the key first
expression(pstate); // should parse until ':'
expression(pstate, 1, true); // should parse until ':'
consume(pstate, TOKEN_COLON, "Expected ':' to mark end of key and start of value!");
// now, parse the value (until comma)
expression(pstate);
expression(pstate, 1, true);
// "pop" the 2 values
valuePopped(pstate, 2);
@@ -587,7 +589,7 @@ static void dot(CParseState *pstate, bool canAssign) {
if (canAssign && match(pstate, TOKEN_EQUAL)) {
writeu8(pstate, OP_LOADCONST);
writeu16(pstate, name);
expression(pstate);
expression(pstate, 1, true);
writeu8(pstate, OP_SETOBJECT);
valuePopped(pstate, 2); // pops key, value & object
} else if (match(pstate, TOKEN_PLUS_PLUS)) { // increment the field
@@ -604,8 +606,9 @@ static void dot(CParseState *pstate, bool canAssign) {
uint8_t args = parseArguments(pstate);
writeu8(pstate, OP_INVOKE);
writeu8(pstate, args);
writeu8(pstate, 1); // TODO
valuePopped(pstate, args); // pops the function & the object but pushes a result
writeu8(pstate, pstate->compiler->expectedValues); // TODO
valuePopped(pstate, args+1); // args + function
valuePushed(pstate, pstate->compiler->expectedValues);
} else {
writeu8(pstate, OP_LOADCONST);
writeu16(pstate, name);
@@ -615,11 +618,11 @@ static void dot(CParseState *pstate, bool canAssign) {
}
static void _index(CParseState *pstate, bool canAssign) {
expression(pstate);
expression(pstate, 1, true);
consume(pstate, TOKEN_RIGHT_BRACKET, "Expected ']' to end index.");
if (canAssign && match(pstate, TOKEN_EQUAL)) {
expression(pstate);
expression(pstate, 1, true);
writeu8(pstate, OP_NEWINDEX);
valuePopped(pstate, 2); // pops key, value & object
} else if (match(pstate, TOKEN_PLUS_PLUS)) { // increment the field
@@ -903,28 +906,44 @@ static void block(CParseState *pstate) {
consume(pstate, TOKEN_END, "'end' expected to end block.'");
}
static void varDeclaration(CParseState *pstate, bool forceLocal) {
uint16_t global = parseVariable(pstate, "Expected identifer!", forceLocal);
static void varDeclaration(CParseState *pstate, bool forceLocal, int expectedValues) {
uint16_t ident = parseVariable(pstate, "Expected identifer!", forceLocal);
expectedValues++;
if (match(pstate, TOKEN_EQUAL)) { // assigning a variable
valuePopped(pstate, 1); // we are expecting a value
// consume all the ','
do {
expression(pstate);
valuePopped(pstate, 1);
int pushed = expression(pstate, expectedValues, false);
valuePushed(pstate, 1);
expectedValues -= pushed;
if (expectedValues < 0) { // these values need to be thrown away
writePop(pstate, -expectedValues);
valuePopped(pstate, -expectedValues);
expectedValues = 1;
}
} while (match(pstate, TOKEN_COMMA));
valuePushed(pstate, 1);
// for any expected value we didn't get
while (expectedValues-- > 0) {
valuePushed(pstate, 1);
writeu8(pstate, OP_NIL);
}
} else if (match(pstate, TOKEN_COMMA)) {
varDeclaration(pstate, forceLocal, expectedValues);
} else {
writeu8(pstate, OP_NIL);
valuePushed(pstate, 1);
}
defineVariable(pstate, global, forceLocal);
defineVariable(pstate, ident, forceLocal);
}
static void ifStatement(CParseState *pstate) {
expression(pstate);
expression(pstate, 1, true);
consume(pstate, TOKEN_THEN, "Expect 'then' after expression.");
int jump = writeJmp(pstate, OP_PEJMP);
@@ -967,7 +986,7 @@ static void ifStatement(CParseState *pstate) {
static void whileStatement(CParseState *pstate) {
int jumpLocation = getChunk(pstate)->count;
expression(pstate);
expression(pstate, 1, true);
consume(pstate, TOKEN_DO, "expected 'do' after conditional expression.");
@@ -1047,12 +1066,20 @@ static void returnStatement(CParseState *pstate) {
if (blockFollow(pstate->current)) { // does this return have a value
writeu8(pstate, OP_NIL);
writeu8(pstate, OP_RETURN);
writeu8(pstate, 1);
return;
}
expression(pstate);
// grab return values
int rvalues = 0;
do {
expression(pstate, 1, true);
rvalues++;
} while (match(pstate, TOKEN_COMMA));
writeu8(pstate, OP_RETURN);
valuePopped(pstate, 1);
writeu8(pstate, rvalues);
valuePopped(pstate, rvalues);
}
static void localFunction(CParseState *pstate) {
@@ -1080,7 +1107,7 @@ static void forLoop(CParseState *pstate) {
// parse conditional
int exitJmp = -1;
if (!match(pstate, TOKEN_EOS)) {
expression(pstate);
expression(pstate, 1, true);
consume(pstate, TOKEN_EOS, "Expected ';' after conditional");
exitJmp = writeJmp(pstate, OP_PEJMP);
@@ -1092,9 +1119,7 @@ static void forLoop(CParseState *pstate) {
int bodyJmp = writeJmp(pstate, OP_JMP);
int iteratorStart = getChunk(pstate)->count;
int savedPushed = pstate->compiler->pushedValues;
expression(pstate);
alignStack(pstate, savedPushed);
expression(pstate, 0, true);
consume(pstate, TOKEN_RIGHT_PAREN, "Expected ')' after iterator");
writeJmpBack(pstate, loopStart);
@@ -1128,21 +1153,36 @@ static void synchronize(CParseState *pstate) {
}
}
static void expression(CParseState *pstate) {
static int expression(CParseState *pstate, int needed, bool forceNeeded) {
int lastExpected = pstate->compiler->expectedValues;
int saved = pstate->compiler->pushedValues + needed;
pstate->compiler->expectedValues = needed;
parsePrecedence(pstate, PREC_ASSIGNMENT);
if (pstate->compiler->pushedValues > saved) {
writePop(pstate, pstate->compiler->pushedValues - saved);
valuePopped(pstate, pstate->compiler->pushedValues - saved);
} else if (forceNeeded && pstate->compiler->pushedValues < saved) {
error(pstate, "Missing expression!");
}
pstate->compiler->expectedValues = lastExpected;
return pstate->compiler->pushedValues - (saved - needed);
}
static void expressionStatement(CParseState *pstate) {
pstate->compiler->savedPushed = pstate->compiler->pushedValues;
if (match(pstate, TOKEN_VAR)) {
varDeclaration(pstate, false);
varDeclaration(pstate, false, 0);
} else if (match(pstate, TOKEN_LOCAL)) {
// force declare a local
if (match(pstate, TOKEN_FUNCTION))
localFunction(pstate); // force local a function
else
varDeclaration(pstate, true); // force local a variable
varDeclaration(pstate, true, 0); // force local a variable
} else if (match(pstate, TOKEN_IF)) {
ifStatement(pstate);
} else if (match(pstate, TOKEN_DO)) {
@@ -1160,7 +1200,8 @@ static void expressionStatement(CParseState *pstate) {
} else if (match(pstate, TOKEN_RETURN)) {
returnStatement(pstate);
} else {
expression(pstate);
// we don't need/want any values on the stack, so call expression with 0 values needed
expression(pstate, 0, false);
}
// realign the stack
@@ -1183,6 +1224,7 @@ static CObjFunction *endCompiler(CParseState *pstate) {
popLocals(pstate, pstate->compiler->scopeDepth); // remove the locals from other scopes
writeu8(pstate, OP_NIL);
writeu8(pstate, OP_RETURN);
writeu8(pstate, 1);
// update pstate to next compiler state
CCompilerState *cachedCCState = pstate->compiler;