some help for writing your http://puredata.org/dev/PdDefinitions ... those are surely not the best wordings, but it adds detail.
comma (atom type): a comma character that is not backslashed, and thus is effective as a message separator in a messagebox.
semicolon (atom type): a semicolon character that is not backslashed, and thus is effective as a message separator in any context. if there was any implicit context (as in a messagebox), semicolon forgets it, and thus you get to write an explicit receiver after every semicolon.
dollar (in general): a nonbackslashed dollar sign followed by one or more digits. in an evaluation, this can be worth a float, symbol or pointer, whatever the corresponding argument in the argument list is.
dollar (atom type): a dollar that is parsed individually; is replaced by the corresponding atom upon evaluation.
dollsym (atom type) (missing): in pd 0.39 and earlier: a dollar (subtitutor) that is at the beginning of an atom, followed by symbol characters. Upon substitution it becomes a symbol, as the corresponding atom gets cast to characters and the symbols are merged to make one resulting symbol.
dollsym (atom type) (missing): in pd 0.40 and earlier: any alternation of dollar (subtitutor) and normal symbol characters. All those dollar substitutors get replaced by corresponding atoms cast to characters and all the parts are merged to make one resulting symbol.
(The backslashing stuff may be important to understand if you expect to modify or generate patches using [textfile] like some people do; in general it's good for understanding the fileformat)
Personally, I called "float" "symbol" "pointer" the stable atoms, whereas I call "comma" "semi" "dollar" "dollsym" the radioactive atoms, because they decay upon being used by messageboxes. the radioactive atoms also only really stay alive inside of messageboxes, so in general in pd you will only see functions/methods for handling stable atoms, not radioactive ones.
I could've put this in the wiki directly, but wanted to make sure it gets noticed (and also I'd like some feedback and to know what you'd change in this). Are there any automatic notifications of changes of wiki pages on puredata.info (as a configurable option, per user) ? I mean by email, just like for sf's bug tracker. It would be good to have this so that all parties involved in modifying pages really know about what's going on. It gives the advantages of mailing-lists to wikis.
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