50 lines
1.7 KiB
Text
50 lines
1.7 KiB
Text
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### On The Use Of Underscores In Word Names
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In brief: don't use underscores in word names.
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There is a good reason for this, and it has to do with how RETRO
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processes strings. By default, underscores in strings are replaced
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by spaces. This is problematic when dealing with words like `var`,
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`const`, and `d:create` which take word names as strings.
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Consider:
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:hello_msg 'hello_user ;
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'test_name var
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#188 !test_name
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In the first case, the `:` prefix handles the token, so the
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underscore is not remapped to a space, creating a word name as
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`hello_msg`. But in the second, the `'` prefix remaps the
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underscore to a space, giving a variable name of `test name`.
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In the third line, the name lookup will fail as `test_name` is
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not defined, so the store will be done to an incorrect address.
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Because of this, it's best to avoid underscores in names.
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Having covered this, if you do need to use them for some reason,
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you can replace `d:add-header` with a version that remaps spaces
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back to underscores before creating the header. The following
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will allow for this.
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~~~
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{{
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:fields @Dictionary , (link) , (xt) , (class) ;
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:invalid-name? dup ASCII:SPACE s:contains-char? ;
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:rewrite [ ASCII:SPACE [ $_ ] case ] s:map ;
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:entry here &call dip !Dictionary ;
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[ [ fields invalid-name? &rewrite if s, (name) ] entry ]
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}}
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#1793 &d:add-header store
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&d:add-header n:inc store
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~~~
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Additional Note:
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Some version of RETRO have included the above patch. The last
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release that will include this by default is 2020.4 as it is
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not needed by the majority of users. If you want to keep it in
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your system, you will need to load it yourself or add it to
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your `package/list.forth` (for Unix users) before building.
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