PlainPrinter

String representation of symbol's kind.

The string representation of this type used as a prefix, including separator

The string representation of this type used as a prefix

Generate text using op, assuming a given precedence level prec.

atPrec vs changePrec

This is to be used when changing precedence inside some sort of parentheses: for instance, to print T[A]usetoText(T) ~ '[' ~ atPrec(GlobalPrec) { toText(A) } ~ ']'`.

If the presence of the parentheses depends on precedence, inserting them manually is most certainly a bug. Use changePrec instead to generate them exactly when needed.

Generate text using op, assuming a given precedence level prec. If new level prec is lower than previous level, put text in parentheses.

atPrec vs changePrec

To pretty-print A op B, you need something like changePrec(parsing.precedence(op, isType)) { toText(a) ~ op ~ toText(b) } // BUGGY that will insert parentheses around A op B if, for instance, the preceding operator has higher precedence.

But that does not handle infix operators with left- or right- associativity.

If op and op' have the same precedence and associativity, A op B op' C parses as (A op B) op' C if op and op' are left-associative, and as A op (B op' C) if they're right-associative, so we need respectively

val isType = ??? // is this a term or type operator?
val prec = parsing.precedence(op, isType)
// either:
changePrec(prec) { toText(a) ~ op ~ atPrec(prec + 1) { toText(b) } } // for left-associative op and op'
// or:
changePrec(prec) { atPrec(prec + 1) { toText(a) } ~ op ~ toText(b) } // for right-associative op and op'

The current precedence level. When pretty-printing arguments of operator op, currentPrecedence must equal op's precedence level, so that pretty-printing expressions using lower-precedence operators can insert parentheses automatically by calling changePrec.

Render elements alternating with sep string

Render elements within lowest precedence

Render element within lowest precedence

Render elements within highest precedence

Render element within highest precedence