svMisc (version 0.9-68)

parseText: Parse a character string as if it was a command entered at the command line

Description

Parse R instructions provided as a string and return the expression if it is correct, or an object of class 'try-error' if it is an incorrect code, or NA if the (last) instruction is incomplete.

Usage

parseText(text, firstline = 1, srcfilename = NULL, encoding = "unknown")

Arguments

text

the character string vector to parse into an R expression.

firstline

the index of first line being parsed in the file. If this is larger than 1, empty lines are added in front of text in order to match the correct position in the file.

srcfilename

a character string with the name of the source file.

encoding

encoding of text, as in parse.

Value

• Returns an expression with the parsed code or NA if the last instruction is correct but incomplete, or an object of class'try-error' with the error message if the code is incorrect.

See Also

captureAll, sourceClipboard, parse

Examples

parseText('1+1')
parseText('1+1; log(10)')
parseText(c('1+1', 'log(10)'))

## Incomplete instruction
parseText('log(')

## Incomplete strings
parseText('text <- "some string')
parseText("text <- 'some string")

## Incomplete names (don't write backtick quoted names on several lines!)
## ...but just in case
parseText('`myvar')

## Wrong instruction
parseText('log)')
}

keyword{ IO }

concept{ parsing expression, incomplete code }