plus-.pegR: Alternative to add_rule.

In mslegrand/pegr: PEG PARSER

Description

Alternative to add_rule.

Usage

## S3 method for class 'pegR'
parser + arg

Arguments

parser,	a peg parser produced by new.parser
arg,	a list or vector specififyin a rule:

Details

arg is a list or vector having 1-4 named components:

• rule (Mandatory) A string containing the peg rule definition For example: c(Rule="COLD<-'brrr'"). The 'Rule' label is optional, but having a rule is mandatory.

• des (optional) A a textual string describing the rule. For example: c(Rule="COLD<-'brrr'", des="Polar" ) A comment must be named.

• act (optional) an action specification. For example c(Rule="COLD<-'brrr'", des="Polar", act=function(v){print("brr"); v} ), An action must be named

Examples

peg<- new.parser()
peg + "A<-'a'" + "B<-'b'" + "C<-'c'"
#to suppress the output use invisible"
invisible(peg + "A<-'a'" + "B<-'b'" + "C<-'c'")
#now add rule D with action and comment using a named character vector
peg + c("D<-'d'", des="capitalize D", act="list(atom='D')")

#now add rule E with action and comment a unnamed character
peg + c( "E<-'e'", "#double E", "{list('EE')}" )

mslegrand/pegr documentation built on May 23, 2019, 7:53 a.m.