parser: Detailed R code parser

In parser: Detailed R source code parser

Description

This is a parser for R code using the same grammar as the usual parser (parse) but structuring the information differently.

Usage

parser(file, encoding = "unknown", text)

Arguments

file	Source file to parse
encoding	Encoding for the file
text	If text is given, then its content is sent to a temporary file, which is then used as the file argument.

Value

The output is a list of expressions similar to the output of parse except that expressions are not associated with an inline srcref information. Instead, each expression has an id attribute that refers to the data.

The data attribute is a data frame with the following columns:

line1,col1,byte1	First line, column, and byte of the symbol (token or expression)
line2,col2,byte2	Last line, column, and byte of the symbol (token or expression)
token	Token type.
id	Unique identifier given to this token or expression
parent	identifier for the expression that contains this token or expression
token.desc	A description of this token type. This is read from the output generated by bison

Note

The location information is different to that of R's parse function, parse structures columns and bytes information to comply with the substring function whereas this function returns the information as an offset to the start of the line.

Author(s)

Romain Francois <[e-mail]>

References

This function is largely inspired from the R core parse function. The C code uses the same grammar as the one used by parse.

The Gnu bison parser generator (http://www.gnu.org/software/bison/) is used to create the C code from the grammar.

See Also

The usual R parser parse

Examples

	

f <- system.file( "example", "f.R", package = "parser" )
out <- parser( f )

parser documentation built on May 2, 2019, 6:49 p.m.