Idiomatically determine all the characters that can be used for symbols: Difference between revisions
Idiomatically determine all the characters that can be used for symbols (view source)
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* [[Idiomatically_determine_all_the_lowercase_and_uppercase_letters|Idiomatically determine all the lowercase and uppercase letters]].
<br><br>
=={{header|ALGOL 68}}==
{{works with|ALGOL 68G|Any - tested with release 2.8.3.win32}}
...should also work with other Algol 68 implementations that use upper-stropping (reserved words in upper-case).<br>
There are a number of different types of symbols that can be defined in Algol 68 (informally as follows):<br>
- identifiers used for variables, constants, structure members, procedures<br>
- monadic operators<br>
- dyadic operators<br>
- mode indicants - used for type names
<br>
Monadic and dyadic operators can be symbolic or have "bold" names. Mode indicants also have "bold" names. When upper-stropping is used, bold words are formed from upper-case letters. Algol 68G also allows underscores in bold words - other implementations of Algol 68 may also allow digits.<br>
In the output, the characters shown for monadic and dyadic operators include the upper-case letters - these can't be mixed with symbols, e.g. +A and B- are not valid operator symbols. Additionally, the only valid two character operator name where ":" is the second character is "=:" - the surlaw operator, perhaps :).<br>
Symbolic operator symbols can be one or two characters, optionally suffixed with := or =:.<br>
The following uses the same approach as the AWK sample, though due to the different symbol types, rather more possible symbols have to be checked.<br>
The sample assumes Windows/Linux is the operating system and the Algol 68 compiler/interpreter can be invoked with "a68". It should be possible to modify it for other operating systems/commands. Only 7-bit ASCII characters > space are considered
<syntaxhighlight lang="algol68">
BEGIN # determine which characters can be in identifiers, etc. by trying to #
# compile test programs #
STRING source name = "_tmp.a68";
STRING a68 command = "a68 " + source name + " > _tmp.err 2>&1";
# attenpts to compile the code with "%" substituted with id, #
# returns 0 if it compiled OK, non-zero otherwise #
PROC attempt compilation = ( STRING template, id )INT:
BEGIN
STRING code := "";
# replace "%" with the identifier in the template #
FOR t pos FROM LWB template TO UPB template DO
code +:= IF template[ t pos ] /= "%"
THEN template[ t pos ]
ELSE id
FI
OD;
# output the source file and try compiling it #
FILE source file;
BOOL open error := IF open( source file, source name, stand out channel ) = 0
THEN
# opened OK - file already exists and #
# will be overwritten #
FALSE
ELSE
# failed to open the file #
# - try creating a new file #
establish( source file, source name, stand out channel ) /= 0
FI;
IF open error
THEN # failed to open the file #
print( ( "Unable to open ", source name, newline ) );
stop
ELSE # file opened OK #
put( source file, ( code ) ); # write source #
close( source file );
system( a68 command ) # compile it #
FI
END # attempt compilation # ;
# attempt to construct all two-charaacter symbols and determine whether #
# they are valid by attempting to compile a program containing them #
# only 7-bit ASCII characters > space are considered #
PROC try = ( STRING template, legend )VOID:
BEGIN
[ 0 : 127 ]BOOL first, second;
FOR i FROM LWB first TO UPB first DO
first[ i ] := second[ i ] := FALSE
OD;
FOR f FROM ABS " " + 1 TO UPB first DO
CHAR fc = REPR f;
IF attempt compilation( template, fc ) = 0
THEN
# this character can be the first character of a symbol #
first[ f ] := TRUE;
FOR s FROM ABS " " + 1 TO UPB second DO
IF NOT second[ s ]
THEN
# haven't found this is a valid second character #
# yet #
IF attempt compilation( template, fc + REPR s ) = 0
THEN
# compiled OK #
second[ s ] := TRUE
FI
FI
OD
FI
OD;
print( ( "Characters valid for ", legend, ":", newline ) );
print( ( " as first: " ) );
FOR c pos FROM LWB first TO UPB first DO
IF first[ c pos ]
THEN print( ( REPR c pos ) )
ELIF second[ c pos ]
THEN print( ( " " ) )
FI
OD;
print( ( newline ) );
print( ( " as other: " ) );
FOR c pos FROM LWB first TO UPB first DO
IF second[ c pos ]
THEN print( ( REPR c pos ) )
ELIF first[ c pos ]
THEN print( ( " " ) )
FI
OD;
print( ( newline ) )
END # try # ;
try( "BEGIN INT %; % := 1 END", "identifiers" );
try( "BEGIN OP % = ( INT a )INT: a; % 1 END", "monadic operators" );
try( "BEGIN PRIO % = 5; OP % = ( INT a, b )INT: a; 1 % 1 END", "dyadic operators" );
try( "BEGIN MODE % = INT; % x; x := 1 END", "mode indicants" )
END
</syntaxhighlight>
{{out}}
<pre>
Characters valid for identifiers:
as first: abcdefghijklmnopqrstuvwxyz
as other: 0123456789_abcdefghijklmnopqrstuvwxyz
Characters valid for monadic operators:
as first: !%& +- ?ABCDEFGHIJKLMNOPQRSTUVWXYZ^ ~
as other: * /<=> ABCDEFGHIJKLMNOPQRSTUVWXYZ _
Characters valid for dyadic operators:
as first: !%&*+-/ <=>?ABCDEFGHIJKLMNOPQRSTUVWXYZ^ ~
as other: * /:<=> ABCDEFGHIJKLMNOPQRSTUVWXYZ _
Characters valid for mode indicants:
as first: ABCDEFGHIJKLMNOPQRSTUVWXYZ
as other: ABCDEFGHIJKLMNOPQRSTUVWXYZ_
</pre>
=={{header|AWK}}==
Line 57 ⟶ 185:
2nd..nth char: 193 bad, 63 ok: 0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz
</pre>
=={{header|Delphi}}==
{{works with|Delphi|6.0}}
{{libheader|SysUtils,StdCtrls}}
This code test the all printable ASCII characters to see if they are valid in symbols. It uses the the Delphi system call "IsValidIdent" to determine what the compiler will accept. It starts by testing single characters identifiers, which tests the first character of the identifier. Then tests the second character. This tells which characters are valid for the rest of an identifier.
<syntaxhighlight lang="Delphi">
procedure ShowValidSymbols(Memo: TMemo);
{Uses Delphi system tool "IsValidIndent" }
{To identify valid characters in indentifiers}
var I: integer;
var TS: string;
var Good,Bad: string;
begin
{Test first characters in a symbol}
Good:=''; Bad:='';
for I:=$21 to $7F do
begin
TS:=Char(I);
if IsValidIdent(TS) then Good:=Good+TS
else Bad:=Bad+TS;
end;
Memo.Lines.Add('First Characters Allowed');
Memo.Lines.Add('Allowed: '+Good);
Memo.Lines.Add('Not Allowed: '+Bad);
{Test remaining characters in a symbol}
Good:=''; Bad:='';
for I:=$21 to $7F do
begin
TS:='A'+Char(I);
if IsValidIdent(TS) then Good:=Good+TS[2]
else Bad:=Bad+TS[2];
end;
Memo.Lines.Add('');
Memo.Lines.Add('Remaining Characters Allowed');
Memo.Lines.Add('Allowed: '+Good);
Memo.Lines.Add('Not Allowed: '+Bad);
end;
</syntaxhighlight>
{{out}}
<pre>
First Characters Allowed
Allowed: ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz
Not Allowed: !"#$%&'()*+,-./0123456789:;<=>?@[\]^`{|}~
Remaining Characters Allowed
Allowed: 0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz
Not Allowed: !"#$%&'()*+,-./:;<=>?@[\]^`{|}~
Elapsed Time: 9.048 ms.
</pre>
=={{header|F_Sharp|F#}}==
Line 823 ⟶ 1,008:
REXX-Regina_3.8.2(MT) 5.00 22 Jun 2014
symbol characters: !#$.0123456789?@ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz
</pre>
=={{header|RPL}}==
The RPL character set is an 8-bit character set, sometimes referred to simply as "ECMA-94" in documentation, although it is for the most part a variant of ISO/IEC 8859-1 / ECMA-94. See the related [https://en.wikipedia.org/wiki/RPL_character_set Wikipedia entry] for more details.
≪ "" "'A '"
1 255 '''FOR''' c
3 c CHR REPL
'''IFERR''' DUP STR→ '''THEN''' DROP
'''ELSE'''
'''IF''' 'A' SAME NOT '''THEN''' SWAP c CHR + SWAP '''END'''
'''END'''
'''NEXT''' DROP
≫ '<span style="color:blue">SYMBOLS</span>' STO
{{out}}
<pre>
1: "!$%&.0123456789?ABCDEFGHIJKLMNOPQRSTUVWXYZ\abcdefghijklmnopqrstuvwxyz~∇∑▶πα→←↓↑γδεηθλρστωΔΠΩ▬∞ ¡¢£¤¥¦§¨©ª¬®¯°±²³´µ¶·¸¹º¼½¾¿ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùúûüýþÿ"
</pre>
Line 866 ⟶ 1,067:
Identifiers which begin with underscores can only be used as instance field names (one underscore) or static field names (two or more underscores).
<syntaxhighlight lang="
for (i in 65..90) System.write(String.fromByte(i))
System.print("_")</syntaxhighlight>
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