# [Clean], <s>386</s> <s>375</s> <s>216</s> 209 bytes

    import StdEnv,Text,Data.List
    r=replaceSubString
    $['if(':s]#(h,[_:t])=span((<>)')')s
    =h++['?': $t]
    $['else ':s]=[':': $s]
    $[a:b]=[a: $b]
    $e=e
    @s=hd[[v,'=']++r[v,'='][](r[';'][]($s))\\['else ',v,'=':_]<-tails s]

[Try it online!][TIO-jn3mqdrn]

[Clean]: https://github.com/Ourous/curated-clean-linux
[TIO-jn3mqdrn]: https://tio.run/##PU/LboMwELzzFZaKZBBQhSvBaQ7poVIOlejNsaIFTLBkG2Q7UfvzdQ0t1R52ZnZnH53koL2a@rvkSIHQXqh5Mg41rn/Vj/yDf7r8BA6ez8K6yBDDZwkdb@5t44zQtyimWAwJrix7SsacXivHUmJn0ElSH1IcwkZkzDKKX3CFYscWB5eWo8VDKK4W2S4yVG0QINA2UE54dLRk7Cl95JhglmXmD1GWGIr3K4html4u28h8baiurC4cCGmRZb5xEB4i6IjWU3Vd7tKQVR0S2e1XoyDlhrZKUf6Xwib/3Q0SbtYXb2d/@tKgRPdL3iW4YTLKF@0P "Clean – Try It Online"