Mixfix pseudocode

MeTTa is written in prefix S-expressions: (+ 1 2), (if (> $n 0) $n 0). Mixfix pseudocode renders the same forms the way you would read them aloud, with operators between their arguments and functions applied to parenthesised arguments: 1 + 2, fact(5).

Turn on pseudocode mode (the settings quick-pick, or metta.pseudocode.enabled) and the server shows each top-level form's mixfix reading as a code lens above it, so you see the meaning of every line without rearranging the parentheses in your head:

(= (fact $n) (* $n (fact (- $n 1))))
; ≡ fact($n) = $n * fact($n - 1)

!(fact 5)
; ≡ fact(5)

The rendering is notation, not English: an infix operator reads infix, a known mixfix form (like if) reads in its mixfix shape, and everything else is function application. It is the same projection the Explain form command uses, so clicking a pseudocode lens opens the fuller reading.