D-Scanner/analysis/range.d

108 lines
2.5 KiB
D

// Copyright Brian Schott (Sir Alaran) 2014.
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
module analysis.range;
import stdx.d.ast;
import stdx.d.lexer;
import analysis.base;
/**
* Checks for .. expressions where the left side is larger than the right. This
* is almost always a mistake.
*/
class BackwardsRangeCheck : BaseAnalyzer
{
alias visit = BaseAnalyzer.visit;
bool hasLeft;
bool hasRight;
long left;
long right;
size_t column;
size_t line;
enum State { ignore, left, right }
State state = State.ignore;
this(string fileName)
{
super(fileName);
}
override void visit(ForeachStatement foreachStatement)
{
if (foreachStatement.low !is null && foreachStatement.high !is null)
{
import std.string;
state = State.left;
foreachStatement.low.accept(this);
state = State.right;
foreachStatement.high.accept(this);
state = State.ignore;
if (hasLeft && hasRight && left > right)
{
string message = format(
"%d is larger than %d. Did you mean to use 'foreach_reverse( ... ; %d .. %d)'?",
left, right, right, left);
addErrorMessage(line, this.column, message);
}
hasLeft = false;
hasRight = false;
}
foreachStatement.accept(this);
}
override void visit(UnaryExpression unary)
{
if (state != State.ignore && unary.primaryExpression is null)
return;
else
unary.accept(this);
}
override void visit(PrimaryExpression primary)
{
import std.conv;
import std.string;
if (state == State.ignore || !isNumberLiteral(primary.primary.type))
return;
if (state == State.left)
{
line = primary.primary.line;
this.column = primary.primary.column;
left = to!long(primary.primary.text.removechars("_"));
hasLeft = true;
}
else
{
right = to!long(primary.primary.text.removechars("_"));
hasRight = true;
}
}
override void visit(SliceExpression sliceExpression)
{
if (sliceExpression.lower !is null && sliceExpression.upper !is null)
{
state = State.left;
sliceExpression.lower.accept(this);
state = State.right;
sliceExpression.upper.accept(this);
state = State.ignore;
if (hasLeft && hasRight && left > right)
{
import std.string;
string message = format(
"%d is larger than %d. This slice is likely incorrect.",
left, right);
addErrorMessage(line, this.column, message);
}
hasLeft = false;
hasRight = false;
}
sliceExpression.accept(this);
}
}