create_tree {evalR}

Convert a statement into an evaluation tree

Description

function will break text into a list of lists.

Usage

create_tree(
  text,
  singular_operators = NULL,
  binary_operators = NULL,
  valid_functions = NULL
)

Arguments

text

the string/code/statement you want to parse.

singular_operators

tokens of length 1 that operate on a right hand value. For example, the '-' token is an operator to negate a vector. NULL value will be replaced with c("-", "!").

binary_operators

tokens of any length that operate on a left and right hand values. For example, the '+' token is an operator that adds a left vector to a right vector. NULL value will be replaced with c(",", "|", "&", "<=", "<", ">=", ">", "==", "!=", "+", "-", "*", "%/%", "/", "%%", "%in%", ":", "^"). The order determines the precedence of the operators.

valid_functions

tokens of any length that are prefixed on a parenthesis block and specify a function to run on the provided parameters within the block. For example, the 'log' token will evaluate the logarithm value of the first parameter. Note named parameters are not support. NULL value will be replaced with c("log", "c", "any", "all", "abs", "ifelse").

Details

See vignette("Overview", package = "evalR")

Value

a list of lists. In other words, a tree data structure made from lists.

Examples

x <- create_tree("2 * (3 + 5)")
str(x)