org.scalastyle.scalariform.RedundantIfChecker.scala Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of scalastyle_2.9.3 Show documentation

Scalastyle style checker for Scala

The newest version!

// Copyright (C) 2011-2012 the original author or authors.
// See the LICENCE.txt file distributed with this work for additional
// information regarding copyright ownership.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package org.scalastyle.scalariform

import org.scalastyle.CombinedAst
import org.scalastyle.CombinedChecker
import org.scalastyle.PositionError
import org.scalastyle.ScalastyleError

import VisitorHelper.visit
import scalariform.lexer.Tokens.ELSE
import scalariform.lexer.Tokens.FALSE
import scalariform.lexer.Tokens.TRUE
import scalariform.lexer.Token
import scalariform.parser.ElseClause
import scalariform.parser.Expr
import scalariform.parser.GeneralTokens
import scalariform.parser.IfExpr

class RedundantIfChecker extends CombinedChecker {
  val errorKey = "if.redundant"

  def verify(ast: CombinedAst): List[ScalastyleError] = {
    val it = for {
      t <- localvisit(ast.compilationUnit);
      if matches(t)
    } yield {
      PositionError(t.firstToken.offset)
    }

    it.toList
  }

  private def matches(t: IfExpr): Boolean =
    isBoolean(t.body) && isBoolean(t.elseClause)

  private def isBoolean(t: Option[ElseClause]): Boolean = t match {
    case Some(ElseClause(None, tok, expr)) => tok.tokenType == ELSE && isBoolean(expr)
    case _ => false
  }
  private def isBoolean(t: Expr): Boolean = t match {
    case Expr(List(GeneralTokens(List(a)))) => isBoolean(a)
    case _ => false
  }
  private def isBoolean(t: Token): Boolean = Set(TRUE, FALSE).contains(t.tokenType)

  private def localvisit(ast: Any): List[IfExpr] = ast match {
    case t: IfExpr if matches(t) => List(t)
    case t: Any => visit(t, localvisit)
  }
}