R: Evaluates an RSP string and outputs the generated string

rcat {R.rsp} | R Documentation

## Evaluates an RSP string and outputs the generated string

### Description

Evaluates an RSP string and outputs the generated string.

### Usage

     ## Default S3 method:
    rcat(..., file=NULL, path=NULL, envir=parent.frame(), args="*", output="", buffered=TRUE,
      append=FALSE, verbose=FALSE)
     ## Default S3 method:
    rsource(file, path=NULL, envir=parent.frame(), output="", buffered=FALSE, ...)

### Arguments

`...` | A `character` string with RSP markup.
`file, path` | Alternatively, a file, a URL or a `connection` from with the strings are read. If a file, the `path` is prepended to the file, iff given.
`envir` | The `environment` in which the RSP string is preprocessed and evaluated.
`args` | A named `list` of arguments assigned to the environment in which the RSP string is parsed and evaluated. See `cmdArgs`.
`output` | A `connection`, or a pathname where to direct the output. If `""`, the output is sent to the standard output.
`buffered` | If `TRUE`, and `output=""`, then the RSP output is outputted as soon as possible, if possible.
`append` | Only applied if `output` specifies a pathname; If `TRUE`, then the output is appended to the file, otherwise the files content is overwritten.
`verbose` | See `Verbose`.

### Value

Returns (invisibly) the outputted `RspStringProduct`.

### Processing RSP strings from the command line

Using `Rscript` and `rcat()`, it is possible to process an RSP string and output the result from the command line. For example,

`Rscript -e "R.rsp::rcat('A random integer in [1,<%=K%>]: <%=sample(1:K, size=1)%>')" --args --K=50`

parses and evaluates the RSP string and outputs the result to standard output.

### rsource()

The `rsource(file, ...)` is a convenient wrapper for `rcat(file=file, ..., output="", buffered=FALSE)`. As an analogue, `rsource()` is to an RSP file what `source()` is to an R script file.

### Author(s)

Henrik Bengtsson

### See Also

To store the output in a string (instead of displaying it), see `rstring`(). For evaluating and postprocessing an RSP document and writing the output to a file, see `rfile`().

### Examples

    rcat("A random integer in [1,100]: <%=sample(1:100, size=1)%>\n")

    # Passing arguments
    rcat("A random integer in [1,<%=K%>]: <%=sample(1:K, size=1)%>\n", args=list(K=50))

[Package R.rsp version 0.41.0 Index]