Check whether a parse table contains a tilde

Check whether a parse table contains a tilde

is_tilde_expr(pd, tilde_pos = c(1L, 2L))

is_asymmetric_tilde_expr(pd)

is_symmetric_tilde_expr(pd)

Arguments

pd

A parse table.

tilde_pos

Integer vector indicating row-indices that should be checked for tilde. See 'Details'.

Details

A tilde is on the top row in the parse table if it is an asymmetric tilde expression (like ~column), in the second row if it is a symmetric tilde expression (like a~b).