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2018-06-28T18:36:20Z

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2008年7月28日 (月) 15:39にwiki>Quornによる

2008-07-28T15:39:38Z

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=Syntax Highlighting=
Committed to gsoc-2008-quorn branch: ['''[http://projects.blender.org/plugins/scmsvn/viewcvs.php?view=rev&root=bf-blender&revision=15837 rev. 15837]''']

==Design==
Calculating syntax highlighting for the whole document for every typed key is
crazy. Since Python is line based, only the current line needs reparsing, with
added consideration for multi-line statements.

Lines only affect the other lines in the following cases:
* Triple quoted strings:
"""Some text in here...
...
"""
* Explicit line joining in other strings:
"This is a string \
over multiple \
lines. " + 'So \
is this.'

The method render_string(st, str) populates temp_char_buf with the string str
(rendered with spaces in place of tabs). The format string is currently the same
length as this for each line.

I propose to keep the linep->format one char longer than temp_char_buf so that
we may keep a flag at the end:
1 0 0 " S o m e t e x t i n t h e l i n e "\0
n n n l l l l l l l l l l l l l l l l l l l l l l l\0\x

Here x is a line continuation flag indicating the starting state of the line to
follow. So lines forming the first part of a multi-line string will end with a
non-zero flag. The value of the flag will indicate the type of string open:
0x00 No strings open
0x01 Single-quoted string open ('...')
0x02 Double-quoted string open ("...")
0x05 Triple single-quoted string open ('''...''')
0x06 Triple double-quoted string open ("""...""")

Example:
Line: 1 0 0 " " " M u l t i - l i n e\0
Format: n n n l l l l l l l l l l l l l\0\6
Line: s t a t e m e n t s\0
Format: l l l l l l l l l l\0\6
Line: g o l i k e t h i s . " " "\0
Format: l l l l l l l l l l l l l l l l\0\0

With this system, a line being edited need only look at the end of the previous
line to work out how to format itself. If its format ends with a continuation
(different to how it started) the next line should be reformatted, and so on
until a non-continuation line is reached (or the continuation doesn't change).

This vastly reduces the need for parsing and will speed up editing of large
files.

==Results==
The original <code>get_format_string</code> method was unnecessarily large and
difficult to understand. Rewriting it I now have two, well commented methods
that are easy to follow: <code>txt_format_line(...)</code> and
<code>txt_format_text(...)</code>, the latter of which achieves the same result
as <code>get_format_string(...)</code> but in much quicker time.

The numbers speak for themselves...

Timing results for 100,000 iterations of the whole document (all lines
reparsed):
Timing syntax highlighting... (small script)
New system took: 2.209049
Old system took: 5.150172
New system took: 2.207988
Old system took: 5.115926
Timing syntax highlighting... (large script)
New system took: 34.184102
Old system took: 81.666011
New system took: 34.200491
Old system took: 80.773203

Since the new system also minimizes the number of lines parsed, this is only the
worst case! Memory is now also allocated in one place reducing the chances of
error.

==Appendix==
New format chars:
'_' Whitespace
'#' Comment text
'!' Punctuation and other symbols
'n' Numerals
'l' String letters
'v' Special variables (class, def)
'b' Built-in names (print, for, etc.)
'q' Other text (identifiers, etc.)

Format chars in prior versions:
'l' Letters (strings)
'b' Built in functions (keywords)
'#' Comments
'v' Special variables ("class" and "def") except
that these are covered by 'b' above so 'v' is
never actually used.
'n' Numbers
'q' Other text, symbols, etc
' ' Whitespace

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Yamyam: 1版 をインポートしました

2008年7月28日 (月) 15:39にwiki>Quornによる

Yamyam: 1版をインポートしました