lean2/src/kernel/formatter.h

/*
Copyright (c) 2013 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.

Author: Leonardo de Moura
*/
#pragma once
#include <memory>
#include "util/sexpr/options.h"
#include "kernel/expr.h"

namespace lean {
/**
   \brief API for formatting expressions
*/
class formatter_cell {
public:
    virtual ~formatter_cell() {}
    /** \brief Format the given expression. */
    virtual format operator()(expr const & e, options const & opts) = 0;
};
/**
   \brief Smart-pointer for the actual formatter object (aka \c formatter_cell).
*/
class formatter {
    std::shared_ptr<formatter_cell> m_cell;
    formatter(formatter_cell * c):m_cell(c) {}
public:
    format operator()(expr const & e, options const & opts = options()) const { return (*m_cell)(e, opts); }
    template<typename FCell> friend formatter mk_formatter(FCell && fcell);
};

template<typename FCell> formatter mk_formatter(FCell && fcell) {
    return formatter(new FCell(std::forward<FCell>(fcell)));
}

std::ostream & operator<<(std::ostream & out, expr const & e);
/**
   \brief Create a simple formatter object based on operator<<
*/
formatter mk_simple_formatter();

typedef std::function<format(formatter const &, options const &)> pp_fn;
}