hlibsass-0.1.2.0: libsass/bind.cpp
#include "bind.hpp"
#include "ast.hpp"
#include "context.hpp"
#include "eval.hpp"
#include <map>
#include <iostream>
#include <sstream>
#include "to_string.hpp"
namespace Sass {
using namespace std;
void bind(string callee, Parameters* ps, Arguments* as, Context& ctx, Env* env, Eval* eval)
{
map<string, Parameter*> param_map;
// Set up a map to ensure named arguments refer to actual parameters. Also
// eval each default value left-to-right, wrt env, populating env as we go.
for (size_t i = 0, L = ps->length(); i < L; ++i) {
Parameter* p = (*ps)[i];
param_map[p->name()] = p;
// if (p->default_value()) {
// env->local_frame()[p->name()] = p->default_value()->perform(eval->with(env));
// }
}
// plug in all args; if we have leftover params, deal with it later
size_t ip = 0, LP = ps->length();
size_t ia = 0, LA = as->length();
while (ia < LA) {
Argument* a = (*as)[ia];
if (ip >= LP) {
// skip empty rest arguments
if (a->is_rest_argument()) {
if (List* l = dynamic_cast<List*>(a->value())) {
if (l->length() == 0) {
++ ia; continue;
}
}
}
stringstream msg;
msg << callee << " only takes " << LP << " arguments; "
<< "given " << LA;
error(msg.str(), as->pstate());
}
Parameter* p = (*ps)[ip];
// If the current parameter is the rest parameter, process and break the loop
if (p->is_rest_parameter()) {
// The next argument by coincidence provides a rest argument
if (a->is_rest_argument()) {
// We should always get a list for rest arguments
if (List* rest = dynamic_cast<List*>(a->value())) {
// arg contains a list
List* args = rest;
// make sure it's an arglist
if (rest->is_arglist()) {
// can pass it through as it was
env->local_frame()[p->name()] = args;
}
// create a new list and wrap each item as an argument
// otherwise we will not be able to fetch it again
else {
// create a new list object for wrapped items
List* arglist = new (ctx.mem) List(p->pstate(),
0,
rest->separator(),
true);
// wrap each item from list as an argument
for (Expression* item : rest->elements()) {
(*arglist) << new (ctx.mem) Argument(item->pstate(),
item,
"",
false,
false);
}
// assign new arglist to environment
env->local_frame()[p->name()] = arglist;
}
}
// invalid state
else {
throw runtime_error("invalid state");
}
} else if (a->is_keyword_argument()) {
// expand keyword arguments into their parameters
List* arglist = new (ctx.mem) List(p->pstate(), 0, List::COMMA, true);
env->local_frame()[p->name()] = arglist;
Map* argmap = static_cast<Map*>(a->value());
for (auto key : argmap->keys()) {
string name = unquote(static_cast<String_Constant*>(key)->value());
(*arglist) << new (ctx.mem) Argument(key->pstate(),
argmap->at(key),
name,
false,
false);
}
} else {
// create a new list object for wrapped items
List* arglist = new (ctx.mem) List(p->pstate(),
0,
List::COMMA,
true);
// consume the next args
while (ia < LA) {
// get and post inc
a = (*as)[ia++];
// wrap current argument into new object
(*arglist) << new (ctx.mem) Argument(a->pstate(),
a->value(),
a->name(),
false,
false);
// check if we have rest argument
if (a->is_rest_argument()) {
// preserve the list separator from rest args
if (List* rest = dynamic_cast<List*>(a->value())) {
arglist->separator(rest->separator());
}
// no more arguments
break;
}
}
// assign new arglist to environment
env->local_frame()[p->name()] = arglist;
}
// consumed parameter
++ip;
// no more paramaters
break;
}
// If the current argument is the rest argument, extract a value for processing
else if (a->is_rest_argument()) {
// normal param and rest arg
List* arglist = static_cast<List*>(a->value());
// empty rest arg - treat all args as default values
if (!arglist->length()) {
break;
}
// otherwise move one of the rest args into the param, converting to argument if necessary
if (arglist->is_arglist()) {
a = static_cast<Argument*>((*arglist)[0]);
} else {
Expression* a_to_convert = (*arglist)[0];
a = new (ctx.mem) Argument(a_to_convert->pstate(),
a_to_convert,
"",
false,
false);
}
arglist->elements().erase(arglist->elements().begin());
if (!arglist->length() || (!arglist->is_arglist() && ip + 1 == LP)) {
++ia;
}
} else if (a->is_keyword_argument()) {
Map* argmap = static_cast<Map*>(a->value());
for (auto key : argmap->keys()) {
string name = "$" + unquote(static_cast<String_Constant*>(key)->value());
if (!param_map.count(name)) {
stringstream msg;
msg << callee << " has no parameter named " << name;
error(msg.str(), a->pstate());
}
env->local_frame()[name] = argmap->at(key);
}
++ia;
continue;
} else {
++ia;
}
if (a->name().empty()) {
if (env->has_local(p->name())) {
stringstream msg;
msg << "parameter " << p->name()
<< " provided more than once in call to " << callee;
error(msg.str(), a->pstate());
}
// ordinal arg -- bind it to the next param
env->local_frame()[p->name()] = a->value();
++ip;
}
else {
// named arg -- bind it to the appropriately named param
if (!param_map.count(a->name())) {
stringstream msg;
msg << callee << " has no parameter named " << a->name();
error(msg.str(), a->pstate());
}
if (param_map[a->name()]->is_rest_parameter()) {
stringstream msg;
msg << "argument " << a->name() << " of " << callee
<< "cannot be used as named argument";
error(msg.str(), a->pstate());
}
if (env->has_local(a->name())) {
stringstream msg;
msg << "parameter " << p->name()
<< "provided more than once in call to " << callee;
error(msg.str(), a->pstate());
}
env->local_frame()[a->name()] = a->value();
}
}
// EO while ia
// If we make it here, we're out of args but may have leftover params.
// That's only okay if they have default values, or were already bound by
// named arguments, or if it's a single rest-param.
for (size_t i = ip; i < LP; ++i) {
To_String to_string(&ctx);
Parameter* leftover = (*ps)[i];
// cerr << "env for default params:" << endl;
// env->print();
// cerr << "********" << endl;
if (!env->has_local(leftover->name())) {
if (leftover->is_rest_parameter()) {
env->local_frame()[leftover->name()] = new (ctx.mem) List(leftover->pstate(),
0,
List::COMMA,
true);
}
else if (leftover->default_value()) {
// make sure to eval the default value in the env that we've been populating
Env* old_env = eval->env;
Backtrace* old_bt = eval->backtrace;
Contextualize* old_context = eval->contextualize;
Expression* dv = leftover->default_value()->perform(eval->with(env, eval->backtrace));
eval->env = old_env;
eval->backtrace = old_bt;
eval->contextualize = old_context;
// dv->perform(&to_string);
env->local_frame()[leftover->name()] = dv;
}
else {
// param is unbound and has no default value -- error
stringstream msg;
msg << "required parameter " << leftover->name()
<< " is missing in call to " << callee;
error(msg.str(), as->pstate());
}
}
}
return;
}
}