lazarus/components/jcf2/Process/Transform/AddBeginEnd.pas

370 lines
9.2 KiB
ObjectPascal

unit AddBeginEnd;
{(*}
(*------------------------------------------------------------------------------
Delphi Code formatter source code
The Original Code is AddBeginEnd.pas, March 2004.
The Initial Developer of the Original Code is Anthony Steele.
Portions created by Anthony Steele are Copyright (C) 1999-2008 Anthony Steele.
All Rights Reserved.
Contributor(s): Anthony Steele.
The contents of this file are subject to the Mozilla Public License Version 1.1
(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.mozilla.org/NPL/
Software distributed under the License is distributed on an "AS IS" basis,
WITHOUT WARRANTY OF ANY KIND, either express or implied.
See the License for the specific language governing rights and limitations
under the License.
Alternatively, the contents of this file may be used under the terms of
the GNU General Public License Version 2 or later (the "GPL")
See http://www.gnu.org/licenses/gpl.html
------------------------------------------------------------------------------*)
{*)}
{$I JcfGlobal.inc}
interface
uses BaseVisitor;
type
TAddBeginEnd = class(TBaseTreeNodeVisitor)
private
protected
public
constructor Create; override;
procedure PostVisitParseTreeNode(const pcNode: TObject); override;
function IsIncludedInSettings: boolean; override;
end;
implementation
uses
SettingsTypes,
ParseTreeNode, ParseTreeNodeType,
JcfSettings, SourceToken, Tokens, TokenUtils;
function IsBlockParent(const pcNode: TParseTreeNode): boolean;
const
BLOCK_PARENTS: TParseTreeNodeTypeSet =
[nIfBlock, nElseBlock, nCaseSelector, nElseCase,
nWhileStatement, nForStatement, nWithStatement];
begin
Result := (pcNode <> nil) and (pcNode.NodeType in BLOCK_PARENTS);
end;
function HasBlockChild(const pcNode: TParseTreeNode): boolean;
var
liDepth: integer;
begin
if pcNode.NodeType = nElseCase then
liDepth := 3
else
liDepth := 2;
{ a compound statement is the begin..end block. }
Result := pcNode.HasChildNode(nCompoundStatement, liDepth);
end;
procedure TestAddSpaceAtEnd(const pcNode: TParseTreeNode);
var
lcLeaf: TSourceToken;
begin
lcLeaf := TSourceToken(pcNode.LastLeaf);
if (lcLeaf = nil) or lcLeaf.IsSolid then
pcNode.AddChild(NewSpace(1));
end;
{
True if the node is an if block that has an else statment
}
function IfStatementHasElse(const pcNode: TParseTreeNode): boolean;
var
lcParent: TParseTreeNode;
begin
Result := False;
if (pcNode <> nil) and (pcNode.NodeType = nIfBlock) then
begin
lcParent := pcNode.Parent;
if lcParent.HasChildNode(nElseBlock, 1) then
Result := True;
end;
end;
{
it is not safe to remove the block from:
case 1:
if <cond1> then
begin
if <cond2> then
<statement1>
end
else
<statement2>;
case 2:
if <cond1> then
if <cond2> then
< statement1>
else
begin
if <cond 3> then
begin
<statement2>
end
end
else
<statement3>;
}
function SafeToRemoveBeginEnd(const pcNode: TParseTreeNode): Boolean;
const
{ if there is an if stament with no else case immediately hereunder,
should find it by this depth }
IMMEDIATE_IF_DEPTH = 4;
MAX_IF_CLIMB = 5;
var
lcParent: TParseTreeNode;
lcChildStmnt: TParseTreeNode;
iLoop: integer;
begin
Result := True;
{ Case 1: is this an if block? }
if (pcNode <> nil) and (pcNode.NodeType = nIfBlock) then
begin
{ does it have an else case after the if block? }
if IfStatementHasElse(pcNode) then
begin
lcChildStmnt := pcNode.GetImmediateChild(nStatement);
{ does the if block contain an if statement? }
if (lcChildStmnt <> nil) and lcChildStmnt.HasChildNode(nIfBlock) then
{ leave the begin-end in place - don't mix up your ifs }
Result := False;
end;
end;
{ case 2 - an else block inside a containing if/else }
if (pcNode <> nil) and (pcNode.NodeType = nElseBlock) then
begin
{ is the else inside an outer if block? }
lcParent := pcNode;
iLoop := 0;
while (iLoop < MAX_IF_CLIMB) and (lcParent <> nil) do
begin
lcParent := lcParent.Parent;
inc(iLoop);
if (lcParent <> nil) and (lcParent.NodeType = nIfBlock) then
break;
end;
if (lcParent <> nil) and (lcParent.NodeType = nIfBlock) then
begin
lcParent := lcParent.Parent;
if (lcParent <> nil) and lcParent.HasChildNode(nElseBlock, 1) then
Result := False;
end;
end;
end;
procedure AddBlockChild(const pcNode: TParseTreeNode);
var
liIndex: integer;
lcTop: TParseTreeNode;
lcStatement, lcCompound, lcStatementList: TParseTreeNode;
lcBegin, lcEnd: TSourceToken;
lcPrior: TSourceToken;
begin
{ this is an if block or the like
with a single statement under it }
if pcNode.NodeType = nElseCase then
lcTop := pcNode.GetImmediateChild(nStatementList)
else
lcTop := pcNode;
lcStatement := lcTop.GetImmediateChild(nStatement);
if lcStatement = nil then
begin
// a dangling else or the like
liIndex := 0;
end
else
begin
liIndex := lcTop.IndexOfChild(lcStatement);
Assert(liIndex >= 0);
end;
{ temporarily take it out }
lcTop.ExtractChild(lcStatement);
{ need some new nodes:
statement
- compound statement
- begin
- statement list
- lcStatement
- end
}
lcCompound := TParseTreeNode.Create;
lcCompound.NodeType := nCompoundStatement;
lcTop.InsertChild(liIndex, lcCompound);
lcBegin := TSourceToken.Create;
lcBegin.SourceCode := 'begin';
lcBegin.TokenType := ttBegin;
lcCompound.AddChild(lcBegin);
lcCompound.AddChild(NewSpace(1));
{ check we have got space before the begin }
lcPrior := lcBegin.PriorToken;
if (lcPrior <> nil) and lcPrior.IsSolid then
lcPrior.Parent.InsertChild(lcPrior.IndexOfSelf + 1, NewSpace(1));
lcStatementList := TParseTreeNode.Create;
lcStatementList.NodeType := nStatementList;
lcCompound.AddChild(lcStatementList);
{ the original statement goes in the middle of this }
if lcStatement <> nil then
lcStatementList.AddChild(lcStatement);
TestAddSpaceAtEnd(lcCompound);
lcEnd := TSourceToken.Create;
lcEnd.SourceCode := 'end';
lcEnd.TokenType := ttEnd;
lcCompound.AddChild(lcEnd);
end;
procedure RemoveBlockChild(const pcNode: TParseTreeNode);
var
lcTop, lcTopStatement: TParseTreeNode;
lcCompoundStatement: TParseTreeNode;
lcStatementList: TParseTreeNode;
lcStatement: TParseTreeNode;
liIndex: integer;
lcComment, lcNext: TSourceToken;
begin
if pcNode.NodeType = nElseCase then
lcTop := pcNode.GetImmediateChild(nStatementList)
else
lcTop := pcNode;
Assert(lcTop <> nil);
lcTopStatement := lcTop.GetImmediateChild(nStatement);
if lcTopStatement = nil then
exit;
liIndex := lcTop.IndexOfChild(lcTopStatement);
Assert(liIndex >= 0);
lcCompoundStatement := lcTopStatement.GetImmediateChild(nCompoundStatement);
if lcCompoundStatement = nil then
exit;
lcStatementList := lcCompoundStatement.GetImmediateChild(nStatementList);
if lcStatementList = nil then
exit;
// if this begin...end owns more than one statement, we can't do it
if lcStatementList.CountImmediateChild(nStatement) > 1 then
exit;
lcStatement := lcStatementList.GetImmediateChild(nStatement);
if lcStatement <> nil then
begin
// right, put this single statement in at the top
lcStatementList.ExtractChild(lcStatement);
lcTop.InsertChild(liIndex, lcStatement);
end;
// find any comments that would be orphaned
if lcTopStatement.HasChildNode(ttComment) then
begin
lcComment := lcTopStatement.FirstLeaf as TSourceToken;
repeat
lcNext := lcComment.NextToken;
if lcComment.TokenType = ttComment then
begin
// keep it
lcComment.Parent.ExtractChild(lcComment);
lcTop.AddChild(lcComment);
if lcComment.CommentStyle = eDoubleSlash then
InsertReturnAfter(lcComment);
end;
lcComment := lcNext;
until (lcComment = nil) or (not lcComment.HasParentNode(lcTopStatement));
end;
// and free the rest of the scaffolding
lcTopStatement.Free;
end;
constructor TAddBeginEnd.Create;
begin
inherited;
HasPostVisit := True;
HasSourceTokenVisit := False;
end;
procedure TAddBeginEnd.PostVisitParseTreeNode(const pcNode: TObject);
var
lcNode: TParseTreeNode;
lcToken: TSourceToken;
begin
lcNode := TParseTreeNode(pcNode);
if not IsBlockParent(lcNode) then
exit;
case FormatSettings.Transform.BeginEndStyle of
eNever:
begin
if HasBlockChild(lcNode) and SafeToRemoveBeginEnd(lcNode) then
RemoveBlockChild(lcNode);
end;
eAlways:
begin
// do not add begin/end to "else if"
if (lcNode.NodeType = nElseBlock) then
begin
lcToken := TSourceToken(lcNode.FirstSolidLeaf);
if (lcToken <> nil) and (lcToken.TokenType = ttIf) then
exit;
end;
if (not HasBlockChild(lcNode)) then
AddBlockChild(lcNode);
end
else
// should not be here
Assert(false);
end;
end;
function TAddBeginEnd.IsIncludedInSettings: boolean;
begin
Result := (FormatSettings.Transform.BeginEndStyle <> eLeave);
end;
end.