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{#######################################################################
# pd_if.R
# This file is part of the R package `parsetools`.
#
# Author: Andrew Redd
# Copyright: 2017 University of Utah
#
# LICENSE
# ========
# The R package `parsetools` is free software:
# you can redistribute it and/or modify it under the terms of the
# GNU General Public License as published by the Free Software
# Foundation, either version 2 of the License, or (at your option)
# any later version.
#
# This software is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see http://www.gnu.org/licenses/.
#
}#######################################################################
#' @name if-statements
#' @title If Statement Nodes
#' @description
#' These function navigate logic statements.
#'
#' @details
#' If statements have the form of the following.
#' ```
#' if (predicate) branch else alternate
#' ```
#' The `predicate` refers to the logical test being performed.
#' The `branch` is the statement or block that is executed if `predicate` evaluates true.
#' The `alternate` is the statement of block that is executed if `predicate` returns false.
#'
#' @inheritParams pd_get_children_ids
#' @example inst/examples/example-pd.R
#' @example inst/examples/example-roots.R
#' @example inst/examples/example-if.R
NULL
#' @describeIn if-statements Is node an if expression.
pd_is_if <-
function(id, pd, .check=TRUE){
if (.check) {
pd <- ._check_parse_data(pd)
id <- ._check_id(id, pd)
}
if (length(id)>1) return(sapply(id, pd_is_if, pd=pd)) #nocov
(token(id) == 'expr') &&
(token(firstborn(id)) == 'IF')
}
is_if <- internal(pd_is_if)
all_if_ids <- make_get_all(pd_is_if)
#' @describeIn if-statements Get the predicate node.
pd_get_if_predicate_id <-
function(id, pd, .check=TRUE){
#' @title Get if predicate id
#' @inheritParams pd_is_if
#' @description
#' Returns the id of the predicate of the if statement,
#' i.e. the conditional statement.
if (.check) {
pd <- ._check_parse_data(pd)
id <- ._check_id(id, pd)
stopifnot(all(is_if(id,pd)))
}
kids <- children(id, pd)
if (length(kids)<5) stop("inproper if statement") #nocov
kids[[3L]]
}
if_predicate <- internal(pd_get_if_predicate_id, all_if_ids(pd))
#' @describeIn if-statements Get the `branch` statement or block node.
pd_get_if_branch_id <-
function(id, pd, .check=TRUE){
#' @title Get branch of if statement.
#' @inheritParams pd_is_if
#' @description
#' Returns the id of the body of the branch executed if the predicate
#' evaluates to true.
if (.check) {
pd <- ._check_parse_data(pd)
id <- ._check_id(id, pd)
stopifnot(all(is_if(id,pd)))
}
kids <- children(id, pd)
if (length(kids)<5) stop("inproper if statement") #nocov
branch.id <- kids[[5L]]
#TODO fix when a comment is in the way.
#' @return an id integer.
}
if_branch <- internal(pd_get_if_branch_id, all_if_ids(pd))
#' @describeIn if-statements Get the `alternate` statement or block node.
pd_get_if_alternate_id <-
function(id, pd, .check=TRUE){
#' @title Get the alternate branch of if statement
#' @inheritParams pd_is_if
#' @description
#' Gets the id of the alternate branch, i.e. the else branch.
if (.check) {
pd <- ._check_parse_data(pd)
id <- ._check_id(id, pd)
stopifnot(all(is_if(id,pd)))
}
kids <- children(id, pd)
if (length(kids)<7 || token(kids[[6]]) != 'ELSE')
stop("inproper if-else statement") #nocov
kids[[7L]]
#' @return an id integer.
}
if_alternate <- internal(pd_get_if_alternate_id, all_if_ids(pd))
if(FALSE){#!@testing if structures
pd <- get_parse_data(parse(text={"
if(predicate){
body
} else {
alternate
}
"}, keep.source=TRUE))
id <- roots(pd) # 33
expect_true(pd_is_if(id,pd))
expect_equal(pd_get_if_predicate_id(id, pd), parent(.find_text('predicate')))
expect_equal(pd_get_if_branch_id (id, pd), parent(parent(.find_text('body'))))
expect_equal(pd_get_if_alternate_id(id, pd), parent(parent(.find_text('alternate'))))
}
|
