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// -*- C++ -*-
// Copyright (C) 2014-2015, Gabriel Dos Reis.
// All rights reserved.
// Written by Gabriel Dos Reis.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// - Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//
// - Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in
// the documentation and/or other materials provided with the
// distribution.
//
// - Neither the name of OpenAxiom. nor the names of its contributors
// may be used to endorse or promote products derived from this
// software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
// IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
// TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
// PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
// OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
// EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// --% Author: Gabriel Dos Reis
#ifndef OPENAXIOM_INPUTFRAGMENT_included
#define OPENAXIOM_INPUTFRAGMENT_included
#include <stdint.h>
#include <vector>
#include <string>
#include <stack>
namespace OpenAxiom {
// Datatypes for locating lines and columns.
using LineNumber = std::size_t;
using ColumnIndex = uint16_t;
enum class LineKind : uint8_t {
Ordinary, // Ordinary input line
Description, // Documentation commentary lines.
Meta, // Input to the attention of the reader
Ignorable, // Ignorable commentary line
};
// A physical line is just raw text, coupled with location
// information such as line and indentation column.
struct Line : std::string {
LineNumber number { };
ColumnIndex indent { };
LineKind kind { LineKind::Ordinary };
std::string sub_string(ColumnIndex s, ColumnIndex e) const {
return substr(s, e - s);
}
};
// Cursor into a fragment.
// Note: We don't expect people to write large fragements
// either in length or in width.
struct FragmentCursor {
uint16_t line; // index of a line in a fragment
uint16_t column; // column number at line.
inline FragmentCursor& operator++() {
++column;
return *this;
}
inline FragmentCursor operator++(int) {
auto tmp = *this;
++*this;
return tmp;
}
inline FragmentCursor& operator--() {
--column;
return *this;
}
inline FragmentCursor operator--(int) {
auto tmp = *this;
--*this;
return tmp;
}
};
std::ostream& operator<<(std::ostream&, FragmentCursor);
// A program fragment is a logical line, composed of possibly
// several physical lines subject to the off-side rule. As a
// special case, a line ending with the underbar character
// continues to the next line with disregard to the off-side rule.
struct Fragment : std::vector<Line> {
explicit operator bool() const { return not empty(); }
// Holds if the last physical line ends with line continuation marker.
bool line_continuation() const {
return not empty() and back().back() == '_';
}
using std::vector<Line>::operator[];
// Reference a line given by a position into this fragment.
const Line& operator()(const FragmentCursor& pos) const {
return (*this)[pos.line];
}
// Reference a character code unit at the position into this fragment.
uint8_t operator[](const FragmentCursor& pos) const {
return (*this)[pos.line][pos.column];
}
// Advance the cursor position to the next character code unit.
uint8_t advance(FragmentCursor& pos) const {
return (*this)[pos.line][pos.column++];
}
// This predicate holds if this fragment covers the cursor position.
bool covering(const FragmentCursor& pos) const {
return pos.column < (*this)[pos.line].size();
}
};
std::ostream& operator<<(std::ostream&, const Fragment&);
}
#endif // OPENAXIOM_INPUTFRAGMENT_included
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