static Value* parseToken(const char** expr, parser_cb* cb) {
Value* ret;
char* token = nextToken(expr);
if(token == NULL) {
return ValErr(badChar(**expr));
}
trimSpaces(expr);
if(**expr == '(') {
(*expr)++;
ArgList* arglist = ArgList_parse(expr, ',', ')', cb);
if(arglist == NULL) {
/* Parse error occurred and has already been raised */
free(token);
return ValErr(ignoreError());
}
ret = ValCall(FuncCall_create(token, arglist));
}
else {
ret = ValVar(token);
}
free(token);
return ret;
}
Value* Expression_eval(Expression* expr, Context* ctx) {
Value* ret;
Variable* var = expr->var;
if(var->type == VAR_VALUE) {
/* Evaluate right side */
ret = Value_eval(var->val, ctx);
/* If an error occurred, bail */
if(ret->type == VAL_ERR)
return ret;
/* Variable assignment? */
if(ret->type == VAL_VAR) {
/* This means ret must be a function */
Variable* func = Variable_get(ctx, ret->name);
if(func == NULL) {
Value* err = ValErr(varNotFound(ret->name));
Value_free(ret);
return err;
}
if(func->type == VAR_BUILTIN) {
Value_free(ret);
return ValErr(typeError("Cannot assign a variable to a builtin value."));
}
if(var->name != NULL) {
Context_setGlobal(ctx, var->name, Variable_copy(func));
}
}
else {
/* This means ret must be a Value */
Value_free(var->val);
var->val = Value_copy(ret);
/* Update ans */
Context_setGlobal(ctx, "ans", Variable_copy(var));
/* Save the newly evaluated variable */
if(var->name != NULL)
Context_setGlobal(ctx, var->name, Variable_copy(var));
}
}
else if(var->type == VAR_FUNC) {
ret = ValVar(var->name);
Context_setGlobal(ctx, var->name, Variable_copy(var));
}
else {
badVarType(var->type);
}
return ret;
}
Value* Value_copy(const Value* val) {
Value* ret;
switch(val->type) {
case VAL_INT:
ret = ValInt(val->ival);
break;
case VAL_REAL:
ret = ValReal(val->rval);
break;
case VAL_FRAC:
ret = ValFrac(Fraction_copy(val->frac));
break;
case VAL_EXPR:
ret = ValExpr(BinOp_copy(val->expr));
break;
case VAL_CALL:
ret = ValCall(FuncCall_copy(val->call));
break;
case VAL_UNARY:
ret = ValUnary(UnOp_copy(val->term));
break;
case VAL_VAR:
ret = ValVar(val->name);
break;
case VAL_VEC:
ret = ValVec(Vector_copy(val->vec));
break;
case VAL_NEG:
/* Shouldn't be reached, but so easy to code */
ret = ValNeg();
break;
case VAL_ERR:
ret = ValErr(Error_copy(val->err));
break;
default:
typeError("Unknown value type: %d.", val->type);
ret = NULL;
break;
}
return ret;
}
Expression* Expression_parse(const char** expr) {
Expression* ret = NULL;
Variable* var;
Value* val;
const char* equals = strchr(*expr, '=');
if(equals == NULL) {
/* No assignment, just a plain expression. */
return parseExpr(expr);
}
/* There is an assignment */
/* First, parse the right side of the assignment */
equals++;
val = Value_parse(&equals, 0, 0);
if(val->type == VAL_ERR) {
/* A parse error occurred */
var = VarErr(Error_copy(val->err));
Value_free(val);
return Expression_new(var);
}
if(val->type == VAL_END) {
/* Empty input */
Value_free(val);
var = VarErr(earlyEnd());
return Expression_new(var);
}
/* Now parse the left side */
char* name = nextToken(expr);
if(name == NULL) {
Value_free(val);
var = VarErr(syntaxError("No variable to assign to."));
return Expression_new(var);
}
trimSpaces(expr);
if(**expr == '(') {
/* Defining a function */
(*expr)++;
/* Array of argument names */
unsigned size = 2;
char** args = fmalloc(size * sizeof(*args));
unsigned len = 0;
/* Add each argument name to the array */
char* arg = nextToken(expr);
if(arg == NULL && **expr != ')') {
/* Invalid character */
Value_free(val);
free(args);
free(name);
var = VarErr(badChar(**expr));
return Expression_new(var);
}
trimSpaces(expr);
if(arg == NULL) {
/* Empty parameter list means function with no args */
free(args);
args = NULL;
len = 0;
}
else {
/* Loop through each argument in the list */
while(**expr == ',' || **expr == ')') {
args[len++] = arg;
if(**expr == ')')
break;
(*expr)++;
/* Expand argument array if it's too small */
if(len >= size) {
size *= 2;
args = frealloc(args, size * sizeof(*args));
}
arg = nextToken(expr);
if(arg == NULL) {
/* Invalid character */
Value_free(val);
free(name);
/* Free argument names and return */
unsigned i;
for(i = 0; i < len; i++) {
free(args[i]);
}
free(args);
var = VarErr(badChar(**expr));
return Expression_new(var);
}
trimSpaces(expr);
}
}
if(**expr != ')') {
/* Invalid character inside argument name list */
Value_free(val);
free(name);
/* Free argument names and return */
unsigned i;
for(i = 0; i < len; i++) {
free(args[i]);
}
free(args);
var = VarErr(badChar(**expr));
return Expression_new(var);
}
/* Skip closing parenthesis */
(*expr)++;
trimSpaces(expr);
if(**expr != '=') {
Value_free(val);
free(name);
unsigned i;
for(i = 0; i < len; i++) {
free(args[i]);
}
free(args);
var = VarErr(badChar(**expr));
return Expression_new(var);
}
/* Construct function and return it */
Function* func = Function_new(len, args, val);
var = VarFunc(name, func);
free(name);
ret = Expression_new(var);
}
else {
/* Defining a variable */
if(**expr != '=') {
/* In-place manipulation */
BINTYPE bin = BinOp_nextType(expr, 0, 0);
/* Still not an equals sign means invalid character */
if(**expr != '=') {
Value_free(val);
free(name);
var = VarErr(badChar(**expr));
return Expression_new(var);
}
val = ValExpr(BinOp_new(bin, ValVar(name), val));
}
var = VarValue(name, val);
free(name);
ret = Expression_new(var);
}
return ret;
}