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Add a paragraph about which identifiers are valid for labels.

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git-svn-id: svn://svn.cc65.org/cc65/trunk@3960 b7a2c559-68d2-44c3-8de9-860c34a00d81
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uz 2009-03-06 10:10:24 +00:00
parent 2575fd1e16
commit fa417d0682
1 changed files with 14 additions and 5 deletions
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19
doc/ca65.sgml
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@ -574,11 +574,20 @@ To force a specific order of evaluation, parentheses may be used, as usual.
<sect>Symbols and labels<p>
A symbol or label is an identifier that starts with a letter and is followed
by letters and digits. Depending on some features enabled (see
<tt><ref id="at_in_identifiers" name="at_in_identifiers"></tt>,
<tt><ref id="dollar_in_identifiers" name="dollar_in_identifiers"></tt> and
<tt><ref id="leading_dot_in_identifiers" name="leading_dot_in_identifiers"></tt>)
other characters may be present. Use of identifiers consisting of a single
character will not work in all cases, because some of these identifiers are
reserved keywords (for example "A" is not a valid identifier for a label,
because it is the keyword for the accumulator).
The assembler allows you to use symbols instead of naked values to make
the source more readable. There are a lot of different ways to define and
use symbols and labels, giving a lot of flexibility.
<sect1>Numeric constants<p>
Numeric constants are defined using the equal sign or the label assignment
@ -2230,7 +2239,7 @@ Here's a list of all control commands and a description, what they do:
<descrip>
<tag><tt>at_in_identifiers</tt></tag>
<tag><tt>at_in_identifiers</tt><label id="at_in_identifiers"></tag>
Accept the at character (`@') as a valid character in identifiers. The
at character is not allowed to start an identifier, even with this
@ -2249,10 +2258,10 @@ Here's a list of all control commands and a description, what they do:
*/ sta $82
</verb></tscreen>
<tag><tt>dollar_in_identifiers</tt></tag>
<tag><tt>dollar_in_identifiers</tt><label id="dollar_in_identifiers"></tag>
Accept the dollar sign (`&dollar;') as a valid character in identifiers. The
at character is not allowed to start an identifier, even with this
dollar character is not allowed to start an identifier, even with this
feature enabled.
<tag><tt>dollar_is_pc</tt></tag>
@ -2266,7 +2275,7 @@ Here's a list of all control commands and a description, what they do:
Allow labels without a trailing colon. These labels are only accepted,
if they start at the beginning of a line (no leading white space).
<tag><tt>leading_dot_in_identifiers</tt></tag>
<tag><tt>leading_dot_in_identifiers</tt><label id="leading_dot_in_identifiers"></tag>
Accept the dot (`.') as the first character of an identifier. This may be
used for example to create macro names that start with a dot emulating