R: Parse Expressions

parse {base} | R Documentation

## Parse Expressions

### Description

`parse` returns the parsed but unevaluated expressions in a list. Each element of the list is of mode `expression`.

### Usage

    parse(file = "", n = NULL, text = NULL, prompt = "?")

### Arguments

`file` | a connection, or a character string giving the name of a file or a URL to read the expressions from. If `file` is `""` and `text` is missing or `NULL` then input is taken from the console.
`n` | the number of statements to parse. If `n` is negative the file is parsed in its entirety.
`text` | character vector. The text to parse. Elements are treated as if they were lines of a file.
`prompt` | the prompt to print when parsing from the keyboard. `NULL` means to use R's prompt, `getOption("prompt")`.

### Details

All versions of R accept input from a connection with end of line marked by LF (as used on Unix), CRLF (as used on DOS/Windows) or CR (as used on classic MacOS). The final line can be incomplete, that is missing the final EOL marker.

See `source` for the limits on the size of functions that can be parsed (by default).

### References

Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.

### See Also

`scan`, `source`, `eval`, `deparse`.

### Examples

    cat("x <- c(1,4)\n  x ^ 3 -10 ; outer(1:7,5:9)\n", file="xyz.Rdmped")
    # parse 3 statements from the file "xyz.Rdmped"
    parse(file = "xyz.Rdmped", n = 3)
    unlink("xyz.Rdmped")

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