revset: parse nullary ":" operator as "0:tip" This is necessary for compatibility with the old-style parser that will be removed by future patches.

parser: take suffix action if no infix action is defined If no infix action is defined, a suffix action isn't ambiguous, so it should be taken no matter if the next token can be an operand. This is exactly the same flow as prefix/primary handling. This change has no effect now because all suffix tokens have infix actions.

parser: reorder infix/suffix handling to be similar to prefix/primary flow It can be exactly the same flow as the prefix/primary handling. A suffix action is accepted only if the next token never starts new term.

parser: resolve ambiguity where both prefix and primary actions are defined If both actions are defined, a primary-expression action is accepted only if the next token never starts new term. For example, parsed as primary expression: ":" # next token 'end' has no action "(:)" # next token ')' has no action ":+y" # next token '+' is infix operator parsed as prefix operator: ":y" # next token 'y' is primary expression ":-y" # next token '-' is prefix operator This is mostly the same resolution as the infix/suffix rules.

parser: separate actions for primary expression and prefix operator This will allow us to define both a primary expression, ":", and a prefix operator, ":y". The ambiguity will be resolved by the next patch. Prefix actions in elements table are adjusted as follows: original prefix primary prefix ----------------- -------- ----------------- ("group", 1, ")") -> n/a ("group", 1, ")") ("negate", 19) -> n/a ("negate", 19) ("symbol",) -> "symbol" n/a

changelog: update read pending documentation The pending index contains a full copy of the index + in-transaction data. We replace "extend" with "overwrite" to make this clearer.