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// -*- C++ -*-
// Copyright (C) 2014-2017, 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.
#include <open-axiom/InputFragment>
#include <algorithm>
#include <iterator>
#include <istream>
#include <ostream>
#include <iostream>
#include <open-axiom/SourceInput>
namespace OpenAxiom {
// Formatting program fragments.
std::ostream& operator<<(std::ostream& os, const Fragment& f) {
std::copy(f.begin(), f.end(),
std::ostream_iterator<std::string>(os, "\n"));
return os;
}
// Return the indentation level of a line.
// FIXME: reject or expand tabs as appropriate.
static ColumnIndex indentation(const Line& line) {
ColumnIndex idx { };
for (auto c : line) {
if (not isblank(c))
break;
++idx;
}
return idx;
}
// Remove trailing white-space characters from the line.
static Line& trim_right(Line& line) {
auto n = line.length();
while (n > 0 and isblank(line[n-1]))
--n;
line.resize(n);
return line;
}
// Return true if line is entirely a positive comment, i.e. a description.
static bool positive_comment(const Line& line) {
if (line.indent + 1 >= line.length())
return false;
return line[line.indent] == '+' and line[line.indent + 1] == '+';
}
// Return true if line is entirely a negative comment.
static bool negative_comment(const Line& line) {
if (line.indent + 1 >= line.length())
return false;
return line[line.indent] == '-' and line[line.indent + 1] == '-';
}
// Clean up and dress up the line with indentation information.
static Line& prop_up(Line& line) {
line.indent = indentation(trim_right(line));
if (negative_comment(line))
line.kind = LineKind::Ignorable;
else if (positive_comment(line))
line.kind = LineKind::Description;
else if (line.indent == 0 and not line.empty() and line.front() == ')')
line.kind = LineKind::Meta;
else
line.kind = LineKind::Ordinary;
return line;
}
// Decompose the input souce file into fragments, and return one
// fragment at a time.
Fragment SourceInput::get() {
Fragment fragment;
std::stack<ColumnIndex> indents;
if (not line.empty()) {
if (line.kind == LineKind::Ordinary)
indents.push(line.indent);
fragment.push_back(line);
}
while (std::getline(input, line)) {
++line.number;
prop_up(line);
if (line.indent >= line.length())
continue; // Don't bother with entirely blank links.
else if (fragment.line_continuation())
; // Line splicing does not change indentation.
else if (line.kind == LineKind::Ignorable)
; // Likewise for ignorable lines.
else if (line.kind == LineKind::Meta)
; // Likewise for reader lines.
else if (line.kind == LineKind::Description and line.indent == 0)
; // Toplevel descriptions preceed items.
else if (indents.empty()) {
// Consecutive rows of wisecracks make up a fragment of their own.
if (line.indent == 0)
break;
else if (fragment.empty())
std::cerr << "warning: white space at begining of fragment"
<< " on line " << line.number << '\n';
indents.push(line.indent);
}
else if (line.indent == 0)
break; // A completely new line; save for later.
else if (line.indent > indents.top())
indents.push(line.indent);
else {
while (line.indent < indents.top())
indents.pop();
}
fragment.push_back(line);
}
return fragment;
}
}
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