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Added iterable objects

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__iter and __next are now reserved IStrings, OP_NEXT and OP_ITER have also been added. A new token (TOKEN_IN) has been added to the lexer. The parser now supports the for each loop (for i, ... in <object> do ... end).
savedPushed has been removed from the CCompilerState struct.
This commit is contained in:
CPunch
2020-12-15 21:21:51 -06:00
parent 4f3f594b82
commit e5eca7bed6
9 changed files with 181 additions and 9 deletions
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76
src/cparse.c
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@@ -35,7 +35,6 @@ typedef struct CCompilerState {
int localCount;
int scopeDepth;
int pushedValues;
int savedPushed;
int expectedValues;
struct CCompilerState* enclosing;
} CCompilerState;
@@ -94,7 +93,6 @@ static void initCompilerState(CParseState* pstate, CCompilerState *ccstate, Func
ccstate->localCount = 0;
ccstate->scopeDepth = 0;
ccstate->pushedValues = 0;
ccstate->savedPushed = 0;
ccstate->expectedValues = 0;
ccstate->type = type;
ccstate->function = cosmoO_newFunction(pstate->state);
@@ -362,6 +360,7 @@ static void alignStack(CParseState *pstate, int alignment) {
writePop(pstate, pstate->compiler->pushedValues - alignment);
} else if (pstate->compiler->pushedValues < alignment) {
error(pstate, "Missing expression!");
printf("%d < %d\n", pstate->compiler->pushedValues, alignment);
}
pstate->compiler->pushedValues = alignment;
@@ -746,6 +745,7 @@ ParseRule ruleTable[] = {
[TOKEN_FUNCTION] = {anonFunction, NULL, PREC_NONE},
[TOKEN_PROTO] = {NULL, NULL, PREC_NONE},
[TOKEN_IF] = {NULL, NULL, PREC_NONE},
[TOKEN_IN] = {NULL, NULL, PREC_NONE},
[TOKEN_LOCAL] = {NULL, NULL, PREC_NONE},
[TOKEN_NOT] = {NULL, NULL, PREC_NONE},
[TOKEN_OR] = {NULL, or_, PREC_OR},
@@ -1091,7 +1091,75 @@ static void localFunction(CParseState *pstate) {
defineVariable(pstate, var, true);
}
static void forEachLoop(CParseState *pstate) {
beginScope(pstate);
// mark a slot on the stack as reserved, we do this by declaring a local with no identifer
Local *local = &pstate->compiler->locals[pstate->compiler->localCount++];
local->depth = pstate->compiler->scopeDepth;
local->isCaptured = false;
local->name.start = "";
local->name.length = 0;
// how many values does it expect the iterator to return?
beginScope(pstate);
int values = 0;
do {
uint16_t funcIdent = parseVariable(pstate, "Expected identifier!", true);
defineVariable(pstate, funcIdent, true);
values++;
} while (match(pstate, TOKEN_COMMA));
if (values > UINT8_MAX) {
error(pstate, "Too many values expected!");
return;
}
// after we consume the values, get the dictionary/object/whatever on the stack
consume(pstate, TOKEN_IN, "Expected 'in' before iterator!");
expression(pstate, 1, true);
consume(pstate, TOKEN_DO, "Expected 'do' before loop block!");
writeu8(pstate, OP_ITER); // checks if stack[top] is iterable and makes an iterable object wrapper for CObjs like CObjDict
int loopStart = getChunk(pstate)->count;
// OP_NEXT expected a uint8_t after the opcode for how many values __next is expected to return
writeu8(pstate, OP_NEXT);
writeu8(pstate, values);
// after the u8, is a u16 with how far to jump if __next returns nil
int jmpPatch = getChunk(pstate)->count;
writeu16(pstate, 0xFFFF); // placeholder, we'll patch this later
// OP_NEXT pushes the values needed
valuePushed(pstate, values);
// compile loop block
beginScope(pstate);
block(pstate);
endScope(pstate);
// pop all of the values, OP_NEXT will repopulate them
endScope(pstate);
// write jmp back to the start of the loop
writeJmpBack(pstate, loopStart);
patchJmp(pstate, jmpPatch); // and finally, patch our OP_NEXT
// remove reserved local
endScope(pstate);
valuePopped(pstate, 1);
}
static void forLoop(CParseState *pstate) {
// first, check if the next token is an identifier. if it is, this is a for loop for an iterator
if (check(pstate, TOKEN_IDENTIFIER)) {
forEachLoop(pstate);
return;
}
beginScope(pstate);
consume(pstate, TOKEN_LEFT_PAREN, "Expected '(' after 'for'");
@@ -1173,7 +1241,7 @@ static int expression(CParseState *pstate, int needed, bool forceNeeded) {
}
static void expressionStatement(CParseState *pstate) {
pstate->compiler->savedPushed = pstate->compiler->pushedValues;
int savedPushed = pstate->compiler->pushedValues;
if (match(pstate, TOKEN_VAR)) {
varDeclaration(pstate, false, 0);
@@ -1205,7 +1273,7 @@ static void expressionStatement(CParseState *pstate) {
}
// realign the stack
alignStack(pstate, pstate->compiler->savedPushed);
alignStack(pstate, savedPushed);
}
static void statement(CParseState *pstate) {