Pattern Matching And Wild Cards - Commodore 1541 User Manual

LOAD"$0:* = S" ,8
will load a directory of all sequential files, while the Basic 3.5 command:
DIRECTORY, "A* =R"
will display a
direct~
consisting only of relative files beginning with the letter ''A'•.
The possible file types , and their abbreviations for this use are:
P = Program
S = Sequential
R =Relative
U =User
D = Deleted
A= Append
M =Modify
PATTERN MATCHING AND WILD CARDS
Just as cassette users can load programs without giving a full name, disk users
ci
use special pattern matching characters to load a program from a partial name. The san
characters can also be used to provide selective directories. The two special charactr
used in pattern matching are the asterisk (*) and the question mark (?). They a
something like a wild card in a game of cards. The difference between the two is that
tl
asterisk makes all characters in and beyond its position wild, while the question mark on
makes its own character position wild. Here are some examples, and their results:
LOAD " A* ",8 loads the first file on disk that begins with an "A", regardless1
what follows . "ARTIST", "ARTERY", and "AZURE" would all qualify , b
"BARRY" wouldn't, even though it has an "A" elsewhere in its name .
DLOAD "SMITH" (Basic 3.5) loads the first program that starts with "SM" , em
with "TH", and has one other character between. This would load " SMITH " 1
"SMYTH", but not "SMYTHE".
OPEN 8,8 ,2,''R?C* ,S,R" We'll study Open in Chapter 5, but the pattern used he
means that the selected file will begin with an "R" and have a "C" in the third charac1 1
of its name.
DIRECTORY,"Q*" (Basic 3.5) will load a directory of files whose names beg•
with "Q".
LOAD"*" ,8 and DLOAD "*"are special cases. When an asterisk is used alone '
a name, it matches the last file used. If none have been used yet on the current diskeV
since turning on the drive, using the asterisk alone loads the first program on the disket1
1
10 INPUT A$ : LOAD A$
+ "
* ", 8 loads any file whose name starts with 1 b
characters entered in A$ .
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fORMAT FOR PATIERN MATCHING :
EXAMPLES:
. *"
"express10n
"C-64*"
or
·•expression?expression''
"C?64 WEDGE"
or
• 'expression?expression*''
"C-64?WED*"
Use any of the above patterns in any of the disk commands whose format includes. a
attem. This applies to Load, Dload, Directory , Open, Scratch , and to the source file m
~e
Copy and Rename commands. More than one"?" can appear in the same pattern ..
As you might expect , their use in pattern matching means you can't use the asterisk
or question mark in a file name when saving or writing a file (see next chapter.)
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