[Tex/LaTex] Nested \ifdefined statements

conditionalsnesting

I am trying to populate a list of variables (in the attached example starting with \@addressone) with the values obtained from a set of commands. The first variable will get the first of whatever values I have, the second the second, etc. until values run out and from then on all the variables shall be empty. I am trying to do this with nested if statements:

\def \mystreet#1{\def\@mystreet{#1}} % Defines the \name command to set name
\def \mycity#1{\def\@mycity{#1}} % Defines the \name command to set name
\def \myphone#1{\def\@myphone{#1}} % Defines the \name command to set name
\def \myemail#1{\def\@myemail{#1}} % Defines the \name command to set name
\def \myurl#1{\def\@myurl{#1}} % Defines the \name command to set name

\let \@mystreet \relax
\let \@mycity \relax
\let \@myphone \relax
\let \@myemail \relax
\let \@myurl \relax

\ifdefined\@mystreet
    \def \@addressone {\@mystreet}
\else
    \ifdefined\@mycity
        \def \@addressone {\@mycity}
    \else
        \ifdefined\@myphone
            \def \@addressone {\@myphone}
        \else
            \ifdefined\@myemail
                \def \@addressone {\@myemail}
            \else
                \ifdefined\@myurl
                    \def \@addressone {\@myurl}
                \else
                    \def \@addressone {}
                \fi
            \fi
        \fi
    \fi
\fi

All of this seems to be ignored beyond the first if statement. If \@mystreet is undefined \@addressone will be empty, even if say \@mycity is defined.

COMMENT: it turns out my issue had nothing to do with the nested \ifdefined statements (which work just as you would expect them to) but rather with how and when LaTeX decided that my user input from files using this class counts as having defined the variables.

Best Answer

The main error is that \relax isn't undefined. This test file is complete and can be run through latex, the terminal output is

macro:->
macro:->streeeet
macro:->ciiity2222

which is (I think) what you want in each of the three cases.

\makeatletter

\def \mystreet#1{\def\@mystreet{#1}} % Defines the \name command to set name
\def \mycity#1{\def\@mycity{#1}} % Defines the \name command to set name
\def \myphone#1{\def\@myphone{#1}} % Defines the \name command to set name
\def \myemail#1{\def\@myemail{#1}} % Defines the \name command to set name
\def \myurl#1{\def\@myurl{#1}} % Defines the \name command to set name


\def\test#1{%
\let \@mystreet \@undefined
\let \@mycity \@undefined
\let \@myphone \@undefined
\let \@myemail \@undefined
\let \@myurl \@undefined
#1%
\ifdefined\@mystreet
    \let\@addressone\@mystreet
\else%
    \ifdefined\@mycity
        \let\@addressone\@mycity
    \else%
        \ifdefined\@myphone
            \ley\@addressone\@myphone
        \else%
            \ifdefined\@myemail
                \let\@addressone \@myemail
            \else%
                \ifdefined\@myurl
                    \let\@addressone\@myurl
                \else
                    \let\@addressone\@empty
                \fi
            \fi
        \fi
    \fi
\fi}

\test{}
\typeout{\meaning\@addressone}


\test{\mystreet{streeeet}\mycity{ciiity}}
\typeout{\meaning\@addressone}


\test{\mycity{ciiity2222}}
\typeout{\meaning\@addressone}


\stop
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