[gnufx]

I don't know why you'd want to write lambda like that.

Long ago, I made a prototype mixfix syntax for Scheme intended for a shell-like REPL with ISWIM overtones. The paren-less function call syntax (terminated by newline or semicolon, like shell) was done by modifying the Pratt engine to treat juxtaposition as application. Sexp syntax was also valid as parenthesized expressions.

[Joker_vD]

Well, when I played with a minimal lambda-calculus evaluator, I quickly got tired of having to print "\" or whatever to denote the start of a lambda. But look, for example, at this:

    (f. (x. f (v. x x v)) (x. f (v. x x v)))
        fct. n.
            (church0? n)
            (_. church1)
             _. church* n (fct (church- n 1))

Are "\" really needed there? You have to put lots parens to denote where lambdas end anyway, and they also happen to show where they start too, and a dot is a clear enough signal for a human (IMHO) to see that it's a lambda. So that's how I've came up with the idea of writing lambdas like that. Then I extended my lambda-calculus evaluator with some arithmetic primitives, and yes, the syntax got somewhat peculiar.