Package 'evalR'

Title: Evaluation of Unverified Code
Description: The purpose of this package is to generate trees and validate unverified code. Trees are made by parsing a statement into a verification tree data structure. This will make it easy to port the statement into another language. Safe statement evaluations are done by executing the verification trees.
Authors: Numerious Inc. [cph, fnd], Trevor Olsen [aut, cre]
Maintainer: Trevor Olsen <[email protected]>
License: MIT + file LICENSE
Version: 0.0.1
Built: 2024-11-27 06:42:55 UTC
Source: CRAN

Help Index

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)

safely evaluate text

Description

Safe alternative to using eval + parse

Usage

eval_text(
  text,
  singular_operators = NULL,
  binary_operators = NULL,
  valid_functions = NULL,
  map = NULL,
  mapping_names = 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").
map

a named list of data.frames/lists/matrices. Where names are keys for referencing the values in the text parameters.
mapping_names

optional argument to make the function faster or limit which map elements can be referenced.

Details

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

Value

numeric or logical vector

Examples

eval_text("1 + 2")

# using the map parameter 
map_obj <- list("#" = data.frame(x = 1:5, y = 5:1),"$" = list(z = -(1:5)))
y <- evalR::eval_text("#x# + $z$", map=map_obj)

safely evaluate tree

Description

Safe alternative to using eval + parse on some string that has already been converted into a tree.

Usage

eval_tree(
  tree,
  singular_operators = NULL,
  binary_operators = NULL,
  valid_functions = NULL,
  map = NULL,
  mapping_names = NULL
)

Arguments

tree

the output object from create_tree
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").
map

a named list of data.frames/lists/matrices. Where names are keys for referencing the values in the text parameters.
mapping_names

optional argument to make the function faster or limit which map elements can be referenced.

Details

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

Value

numeric or logical vector

Examples

tree <- create_tree("1 + 2")
eval_tree(tree)

Helper to find first block of parenthesis

Description

This function will search for the first block of parenthesis and return it if found. Otherwise, it will return "".

Usage

find_parenthesis(text)

Arguments

text

the string/code/statement you want to parse.

Value

a substring. Either "" or the first parenthesis block.

Examples

# returns ""
find_parenthesis("3 + 5")
# returns "(3 + 5)"
find_parenthesis("2 * (3 + 5)")