Syntax highlighting using Mediawiki formatting: Difference between revisions
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or enclose them in <nowiki> tags. |
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If your language doesn't have keywords/reserved words or comments, use your judgement on what to highlight in bold or italic : ) |
If your language doesn't have keywords/reserved words or comments, use your judgement on what to highlight in bold or italic : ) |
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Revision as of 17:53, 7 October 2023
Syntax highlighting using Mediawiki formatting is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.
Introduction
When formatting a page for display, Mediawiki allows the page to include bold and italic text by placing the bold/italic text within paired repeated-single quote characters - 3 single quotes for bold and 2 for italic, 5 for bold italic.
E.g.:
'''bold-word''' and ''italic-word'' appears as bold-word and italic-word.
This could be used to provide simple syntax-highlighting without the use of the relatively more expensive <syntachighlight> tags or for languages not currently supported by Pygments.
A few languages on Rosetta Code are currently using schemes like this.
- Task
The task is to write a syntax highlighter that given a source in your language will output a wiki formatted version of the source with the keywords/reserved words in bold and the comments in italics.
Note that each source line (including blank lines) should be output with a leading space, to ensure the source is treated as a single block.
Additionally, translate the following characters:
- single-quote (') to '
- ampersand (&) to &
- less-than (<) to <
- greater-than (>) to >
If your language doesn't have keywords/reserved words or comments, use your judgement on what to highlight in bold or italic : )
Presenting your source
Instead of showing your source within syntaxhighlight tags and having a separate output block, just show the source that would be output from your program when given its own source to process.
I.e., don't use syntaxhighlight tags.
See also
https://www.mediawiki.org/wiki/Help:Formatting
ALGOL 68
Handles upper-stropping Algol 68 sources (as used by ALGOL 68G and most other compilers).
# Convert an upper-stropped Algol 68 source to "wiki" format #
# each line is preceeded by a space, #
# bold words are enclosed in ''' and ''' and comments in '' and '' #
# ', &, < and > are converted to ' & < and > #
# everything else if output as is #
# the source is read from stand in and written to stand out #
# the last line in the file must end with a newline #
# { and } are assumed to be alternatives for ( and ), if { } should be #
# treated as comments ( as in ALGOL68RS/algol68toc ) #
# change rs style brief comments to TRUE #
BEGIN
# TRUE if {} delimits a nestable brief comment, as in ALGOL 68RS and #
# algol68toc, FALSE if {} are alternatives to () as in ALGOL 68G #
BOOL rs style brief comments = FALSE;
BOOL at eof := FALSE; # TRUE if EOF has been reached, FALSE otherwise #
on logical file end( stand in # set EOF handler for stand in #
, ( REF FILE f )BOOL:
# note that we reached EOF on the latest read #
# and return TRUE so processing can continue #
at eof := TRUE
);
CHAR nl = REPR 10; # newline character #
INT error count := 0; # number of errors reported #
STRING line := nl; # current source line #
INT pos := LWB line; # current position in line #
CHAR c := " "; # current source character #
PROC error = ( STRING message )VOID: # reports an error #
BEGIN
error count +:= 1;
print( ( newline, newline, "**** ", message, newline ) )
END # error # ;
# reports an unterminated construct ( e.g. string, comment ) #
PROC unterminated = ( STRING construct )VOID: error( "Unterminated " + construct );
PROC next char = VOID: # gets the next source character, stores it in c #
IF pos <= UPB line THEN
c := line[ pos ]; # not past the end of the source line #
pos +:= 1
ELIF # past the end of the current source line - get the next #
at eof := FALSE;
read( ( line, newline ) );
NOT at eof
THEN
line +:= nl; # have another line #
pos := LWB line;
c := line[ pos ];
pos +:= 1
ELSE
line := ""; # reached eof #
c := REPR 0
FI # next char # ;
PROC out char = ( CHAR ch )VOID: # conveerts and outputs ch #
IF ch = nl THEN print( ( newline, " " ) )
ELIF ch = "<" THEN print( ( "<" ) )
ELIF ch = ">" THEN print( ( ">" ) )
ELIF ch = "&" THEN print( ( "&" ) )
ELIF ch = "'" THEN print( ( "'" ) )
ELSE print( ch )
FI # out char # ;
# outputs a wiki start/end italic delimiter #
PROC italic delimiter = VOID: print( ( "''" ) );
# outputs a wiki start/end bold delimiter #
PROC bold delimiter = VOID: print( ( "'''" ) );
# returns TRUE if the current character is a string delimiter #
PROC have string delimiter = BOOL: c = """";
# returns TRUE if the current character can start a bold word #
PROC have bold = BOOL: c >= "A" AND c <= "Z";
# outputs a brief comment to stand out #
# end char is the closing delimiter, #
# nested char is the opening delimiter for nestable brief comments #
# if nested char is blank, the brief comment does not nest #
# this handles ALGOL 68RS and algol68toc style {} comments #
PROC copy brief comment = ( CHAR end char, CHAR nested char )VOID:
BEGIN
out char( c );
WHILE next char;
NOT at eof AND c /= end char
DO
IF c = nested char AND nested char /= " " THEN
# nested brief comment #
copy brief comment( end char, nested char )
ELSE
# notmal comment char #
out char( c )
FI
OD;
IF at eof THEN
# unterminated comment #
unterminated( """" + end char + """ comment" );
c := end char
FI;
out char( c );
next char
END # copy brief comment # ;
PROC copy string = VOID: # outputs a string denotation from the source #
WHILE have string delimiter DO # within a string denotation, #
WHILE out char( c ); # "" denotes the " character #
next char;
NOT at eof AND NOT have string delimiter
DO SKIP OD;
IF NOT have string delimiter THEN
unterminated( "string" );
c := """"
FI;
out char( c );
next char
OD # copy string # ;
PROC get bold word = STRING: # gets a bold word from then source #
BEGIN
STRING result := "";
WHILE have bold OR c = "_" DO result +:= c; next char OD;
result
END # get bold word # ;
PROC copy to bold = STRING: # copies the source to the output #
IF at eof # until a bold word is encountered #
THEN ""
ELSE STRING result := "";
WHILE out char( c );
next char;
NOT at eof
AND NOT have bold
DO SKIP OD;
IF NOT at eof THEN result := get bold word FI;
result
FI # copy to bold # ;
PROC bold word or comment = VOID: # handles a bold COMMENT #
IF STRING bold word := get bold word; # or other bold word #
bold word = "CO" OR bold word = "COMMENT"
THEN
italic delimiter; # have a bold comment #
STRING delimiter = bold word;
WHILE print( ( bold word ) );
bold word := copy to bold;
NOT at eof
AND bold word /= delimiter
DO SKIP OD;
IF at eof THEN
unterminated( """" + delimiter + """ comment" )
FI;
print( ( delimiter ) );
italic delimiter
ELSE # some other bold word #
bold delimiter;
print( ( bold word ) );
bold delimiter
FI # bold word or comment # ;
# copy the source to stand out, conveerting to wiki format #
next char;
WHILE NOT at eof DO
IF c = "#" THEN # brief comment #
italic delimiter;
copy brief comment( "#", " " );
italic delimiter
ELIF c = "{" AND rs style brief comments THEN
# nestable brief comment ( ALGOL 68RS and algol68toc ) #
italic delimiter;
copy brief comment( "}", "{" );
italic delimiter
ELIF have string delimiter THEN # STRING or CHAR denotation #
copy string
ELIF have bold THEN # have a bold word #
bold word or comment
ELSE
# anything else #
out char( c );
next char
FI
OD;
IF error count > 0 THEN
# had errors processing the source #
print( ( "**** ", whole( error count, 0 ), " errors", newline ) )
FI
END
AWK
Parsing of patterns may not be correct in all cases.
# convert an AWK source to wiki format
# each line is preceeded by a space,
# reserved words are enclosed in ''' and ''' and comments in '' and ''
# ', &, < and > are converted to ' & < and >
# everything else if output as is
# the wiki source is written to stdout
BEGIN \
{
# reserved word list as in gawk and treating getline as reserved
kw = "BEGIN/BEGINFILE/END/ENDFILE/" \
"break/case/continue/default/delete/do/while/else/" \
"exit/for/in/function/func/if/next/nextfile/switch/" \
"getline";
n = split( kw, reservedWords, "/" );
for( w = 1; w <= n; w ++ )
{
reserved[ reservedWords[ w ] ] = w;
}
} # BEGIN
{
printf( " " );
line = $0;
gsub( /&/, "\\&", line );
gsub( /</, "\\<", line );
gsub( />/, "\\>", line );
gsub( /'/, "\\'", line );
if( line != "" )
{
c = "";
nextChar();
do
{
if ( c == "#" )
{
# comment
printf( "''#%s''", line );
c = "";
}
else if( c == "\"" )
{
# string literal
do
{
if( c == "\\" )
{
printf( "%s", c );
nextChar();
}
printf( "%s", c );
nextChar();
}
while( c != "\"" && c != "" );
if( c != "\"" )
{
printf( "**** Unterminated string\n" );
}
else
{
nextChar();
}
printf( "\"" );
}
else if( c == "/" && lastC !~ /[A-Za-z0-9_.]/ )
{
# pattern
bracketDepth = 0;
printf( "%s", c );
nextChar();
while( c != "" && ( c != "/" || bracketDepth > 0 ) )
{
if( c == "\\" || c == "[" )
{
if ( c == "[" )
{
bracketDepth ++;
}
printf( "%s", c );
nextChar();
}
else if( c == "]" )
{
bracketDepth --;
}
printf( "%s", c );
nextChar();
}
if( c != "/" )
{
printf( "**** Unterminated pattern\n" );
}
else
{
nextChar();
}
printf( "/" );
}
else if( c ~ /[A-Za-z]/ )
{
# have a reserved word or identifier
word = "";
do
{
word = word c;
nextChar();
}
while( c ~ /[A-Za-z0-9_]/ );
if( word in reserved )
{
word = "'''" word "'''";
}
printf( "%s", word );
}
else
{
# something else
printf( "%s", c );
nextChar();
}
}
while( c != "" );
}
printf( "\n" );
}
function nextChar()
{
if( c != " " )
{
# the last character wasn't a space, save it so we can recognise patterns
lastC = c;
}
if( line == "" )
{
# at end of line
c = "";
}
else
{
# not end of line
c = substr( line, 1, 1 );
line = substr( line, 2 );
}
} # nextChar