Walk the Abstract Syntax Tree (AST) of an R Expression

walkAST(
  expr,
  atomic = NULL,
  name = NULL,
  call = NULL,
  pairlist = NULL,
  substitute = FALSE
)

Arguments

expr

R expression.

atomic, name, call, pairlist

single-argument function that takes an atomic, name, call and pairlist expression, respectively. Have to return a valid R expression.

name

single-argument function that takes a name expression.

call

single-argument function that takes a call expression.

pairlist

single-argument function that takes a pairlist expression.

substitute

If TRUE, expr is substitute():ed.

Value

R expression.