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###########################################################################/**
# @RdocDefault indexOfNonQuoted
#
# @title "Gets the first index of a string that is not inside a double quoted string"
#
# \description{
# @get "title".
# }
#
# @synopsis
#
# \arguments{
# \item{str}{The @character string to be scanned.}
# \item{pattern}{The @character string to be searched for.}
# \item{...}{Not used.}
# }
#
# \value{
# Returns an @integer giving the position of (the first character of)
# the search string in the main string. If not found, -1 is returned.
# }
#
# @author
#
# \seealso{
# @see "base::grep".
# }
#
# @keyword programming
# @keyword utilities
# @keyword internal
#*/###########################################################################
setMethodS3("indexOfNonQuoted", "default", function(str, pattern, ...) {
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
# Validate arguments
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
# Argument 'str':
str <- as.character(str)
# Argument 'pattern':
pattern <- as.character(pattern)
totalPos <- 0L; # The position from the start of the string
len <- 0L; # The default match length
qm <- NULL; # The current quotation mark of a string, if exists.
ready <- FALSE
while(!ready) {
# Get the first occurance of pattern in buffer
pos <- regexpr(pattern, str)
if (pos == -1L) return(-1L)
totalPos <- totalPos + pos
tmp <- substring(str, first=1L, last=pos-1L)
# a. Remove all espaced (doubled) backslashes, i.e. '\\'
# (A backslash has to be escaped in C gsub(), i.e. '\\'. Each of
# these two backslashes has in turn to be escaped in R doubleing
# the number of backslashes again!)
tmp <- gsub("\\\\\\\\", "", tmp)
# b. Remove all espaced quotes, i.e. '\"'.
tmp <- gsub("\\\\[\"\']", "", tmp)
# c. Remove all non quotes
tmp <- gsub("[^'\"]", "", tmp)
# d. Exclude all single or double quoted strings.
while (nchar(tmp) > 0L) {
if (is.null(qm)) {
# d. Get first quotation mark
qm <- substring(tmp, first=1L, last=1L)
tmp <- substring(tmp, first=2L)
}
# e. Exclude first (single or double) quoted string.
if (qm == "'") {
pattern <- "^[^']*'"
} else {
pattern <- "^[^\"]*\""
}
if (regexpr(pattern, str) != -1L) {
str <- gsub(pattern, "", str)
qm <- NULL
}
} # while (...)
len <- attr(pos, "match.length")
str <- substring(str, first=pos+len)
ready <- is.null(qm)
} # while (!ready)
# The found position
pos <- as.integer(totalPos)
attr(pos, "match.length") <- len
pos
}, protected=TRUE) # indexOfNonQuoted()
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