Difference between revisions of "Fully automatic indentation"
Line 9: | Line 9: | ||
==Amount of indent== | ==Amount of indent== | ||
− | Let's keep it simple and assume one | + | Let's keep it simple and assume one tab size. Open questions are: |
*How much indent | *How much indent | ||
*Use tabs | *Use tabs |
Revision as of 14:54, 14 November 2009
Overview
The source editor should auto indent on pressing return/enter, on paste and when inserting auto generated code. This depends on language and user preferences. Most other editors use either a fixed set of rules or a set of options to configure the rules. This is semi automatic indentation. These options are either too simple or too complex. And they only allow one set of rules, so editing sources with different policies is difficult.
Fully automatic indentation tries to guess the rules from the surrounding code.
Examples
Amount of indent
Let's keep it simple and assume one tab size. Open questions are:
- How much indent
- Use tabs
- long lines
- Special cases
Examples
Sometimes record and classes are aligned to the keywords instead of start of last line.
<Delphi> type TMyRecord = record
i: integer; end;
</Delphi>
begin end
<Delphi> procedure Do; var
i: integer; // indent after var
begin // no indent after procedure, no indent before procedure-begin, unindent after var section
if expr then begin // no indent after then, no indent before then-begin Code; // indent after begin end; // unindent before end
end; </Delphi>
<Delphi> procedure Do; begin
if expr then begin Code; // indent after begin end; // unindent before end
end; </Delphi>
<Delphi> procedure Do; begin
if expr then begin // indent after then and unindent after then-statement Code; // no indent after begin end; // no unindent before end
end; </Delphi>
<Delphi> procedure Do; begin
if expr then begin // indent after then and unindent after then-statement Code; // indent after begin end; // unindent before end
end; </Delphi>
repeat until
I never saw code other than this:
<Delphi> repeat
Code; // indent after repeat
until ; // unindent before until </Delphi>
try finally
I never saw code other than this:
<Delphi> try
Code; // indent after try
finally // unindent before finally
on e do ; // indent after finally
end; // unindent before finally-end </Delphi>
case of end
<Delphi> case expr of 1: ; // no indent after case-of 2:
Code; // indent after case-colon
const:
begin // indent after case-colon Code; // indent after case-colon-begin end; // unindent before case-colon-end, unindent after case-colon-end
else // no indent case-else
Code; // indent after case-else
end; // unindent after case-else statements </Delphi>
<Delphi> case expr of
// empty lines => not supported 1: ; // indent after case-of
2: begin // no indent after case-colon end;
else // no indent before case-else end; // no indent before case-end </Delphi>
if then else
<Delphi> if expr then
Code
else
Code;
</delphi>
<Delphi> if expr or
expr or expr then Code
else
Code;
</delphi>
<Delphi> if expr
or expr
then
Code
else
Code;
</delphi>
<Delphi> if SrcEdit.SelectionAvailable and SrcEdit.CaretInSelection(CaretPos) then Expression := SrcEdit.GetText(True) else Expression := Identifier; if not DebugBoss.Evaluate(Expression, DebugEval) or (DebugEval = ) then DebugEval := '???'; </delphi>