README.Rmd

---
output: 
  github_document
---

<!-- README.md is generated from README.Rmd. Please edit that file -->

```{r setup, include = FALSE}
knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>",
  fig.path = "man/figures/README-",
  out.width = "100%"
)
library(postlogic)
```
# `postlogic` <img src="man/figures/logo.png" align="right" height=140/>
[![Travis build status](https://travis-ci.org/RDocTaskForce/postlogic.svg?branch=master)](https://travis-ci.org/RDocTaskForce/postlogic)
[![Coverage status](https://codecov.io/gh/RDocTaskForce/postlogic/branch/master/graph/badge.svg)](https://codecov.io/github/RDocTaskForce/postlogic?branch=master)
[![CRAN version](http://www.r-pkg.org/badges/version/postlogic)](https://cran.r-project.org/package=postlogic)
[![lifecycle](https://img.shields.io/badge/lifecycle-experimental-orange.svg)](https://www.tidyverse.org/lifecycle/#experimental)

The goal of postlogic is to allow natural flowing logic statements.

## Installation

You can install the released version of postlogic from [CRAN](https://CRAN.R-project.org) with:

``` r
install.packages("postlogic")
```

## If/Otherwise

The if/otherwise instruction allows for simple logic to follow a statement
to make it conditional.  The `%if%` can be used alone to make an action conditional.

```{r example}
verbose <- TRUE 
message("Hello there") %if% verbose
```

When combined with the `%otherwise%` statement it allows for an alternate.

```{r angry}
mood <- "calm"
message("How dare you!") %if% (mood == 'angry') %otherwise% 
    message("Everything is fine.")

mood <- 'angry'
message("How dare you!") %if% (mood == 'angry') %otherwise% 
    message("Everything is fine.")
```

## Unless/Then

The `%unless%` operator is essentially the negation of `%if%`.
So when a statement is postfixed by an `%unless%` statement it will happen
unless the proposition returns `TRUE`.  The alternating operator for 
`%unless%` is `%then%`.

```{r}
mood <- 'calm'
message("Everything is fine.") %unless% (mood == 'angry') %then% 
    message("How dare you!")
```

This example is the same effect as the statements in the previous example.

## Documentation

The `postlogic` package is developed by the R Documentation Task Force, an 
[R Consortium](https://www.r-consortium.org)
[Infrastructure Steering Committee working group](https://www.r-consortium.org/projects/isc-working-groups).