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// file : libbuild2/functions-builtin.cxx -*- C++ -*-
// license : MIT; see accompanying LICENSE file
#include <sstream>
#include <libbuild2/scope.hxx>
#include <libbuild2/function.hxx>
#include <libbuild2/variable.hxx>
using namespace std;
namespace build2
{
// Note: not static since used by type-specific sort() implementations.
//
bool
functions_sort_flags (optional<names> fs)
{
bool r (false);
if (fs)
{
for (name& f: *fs)
{
string s (convert<string> (move (f)));
if (s == "dedup")
r = true;
else
throw invalid_argument ("invalid flag '" + s + '\'');
}
}
return r;
};
void
builtin_functions (function_map& m)
{
function_family f (m, "builtin");
// $defined(<variable>)
//
// Return true if the specified variable is defined in the calling scope or
// any outer scopes.
//
// Note that this function is not pure.
//
// Note that we may want to extend the scope argument to a more general
// notion of "lookup context" (scope, target, prerequisite).
//
f.insert ("defined", false) += [](const scope* s, names name)
{
if (s == nullptr)
fail << "defined() called out of scope" << endf;
return (*s)[convert<string> (move (name))].defined ();
};
// $visibility(<variable>)
//
// Return variable visibility if it is known and `null` otherwise.
//
// Possible visibility value are:
//
// global -- all outer scopes
// project -- this project (no outer projects)
// scope -- this scope (no outer scopes)
// target -- target and target type/pattern-specific
// prereq -- prerequisite-specific
//
// Note that this function is not pure.
//
f.insert ("visibility", false) += [](const scope* s, names name)
{
if (s == nullptr)
fail << "visibility() called out of scope" << endf;
const variable* var (
s->var_pool ().find (convert<string> (move (name))));
return (var != nullptr
? optional<string> (to_string (var->visibility))
: nullopt);
};
// $type(<value>)
//
// Return the type name of the value or empty string if untyped.
//
f["type"] += [](value* v) {return v->type != nullptr ? v->type->name : "";};
// $null(<value>)
//
// Return true if the value is `null`.
//
f["null"] += [](value* v) {return v->null;};
// $empty(<value>)
//
// Return true if the value is empty.
//
f["empty"] += [](value* v) {return v->null || v->empty ();};
// $first(<value>[, <not_pair>])
// $second(<value>[, <not_pair>])
//
// Return the first or the second half of a pair, respectively. If a value
// is not a pair, then return `null` unless the <not_pair> argument is
// `true`, in which case return the non-pair value.
//
// If multiple pairs are specified, then return the list of first/second
// halfs. If an element is not a pair, then omit it from the resulting
// list unless the <not_pair> argument is `true`, in which case add the
// non-pair element to the list.
//
f["first"] += [] (names ns, optional<value> not_pair)
{
// @@ TODO: would be nice to return typed half if passed typed value.
bool np (not_pair && convert<bool> (move (*not_pair)));
names r;
for (auto i (ns.begin ()), e (ns.end ()); i != e; )
{
name& f (*i++);
name* s (f.pair ? &*i++ : nullptr);
if (s != nullptr || np)
{
f.pair = '\0';
r.push_back (move (f));
}
else if (ns.size () == 1)
return value (nullptr); // Single non-pair.
}
return value (move (r));
};
f["second"] += [] (names ns, optional<value> not_pair)
{
bool np (not_pair && convert<bool> (move (*not_pair)));
names r;
for (auto i (ns.begin ()), e (ns.end ()); i != e; )
{
name& f (*i++);
name* s (f.pair ? &*i++ : nullptr);
if (s != nullptr)
r.push_back (move (*s));
else if (np)
r.push_back (move (f));
else if (ns.size () == 1)
return value (nullptr); // Single non-pair.
}
return value (move (r));
};
// Leave this one undocumented for now since it's unclear why would anyone
// want to use it currently (we don't yet have any function composition
// facilities).
//
f["identity"] += [](value* v) {return move (*v);};
// $quote(<value>[, <escape>])
//
// Quote the value returning its string representation. If <escape> is
// `true`, then also escape (with a backslash) the quote characters being
// added (this is useful if the result will be re-parsed, for example as a
// script command line).
//
f["quote"] += [](value* v, optional<value> escape)
{
if (v->null)
return string ();
untypify (*v, true /* reduce */); // Reverse to names.
ostringstream os;
to_stream (os,
v->as<names> (),
quote_mode::normal,
'@' /* pair */,
escape && convert<bool> (move (*escape)));
return os.str ();
};
// $getenv(<name>)
//
// Get the value of the environment variable. Return `null` if the
// environment variable is not set.
//
// Note that if the build result can be affected by the variable being
// queried, then it should be reported with the `config.environment`
// directive.
//
// Note that this function is not pure.
//
f.insert ("getenv", false) += [](names name)
{
optional<string> v (getenv (convert<string> (move (name))));
if (!v)
return value ();
names r;
r.emplace_back (to_name (move (*v)));
return value (move (r));
};
}
}
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