AlignRegex

Overview

Align either pre-defined or user-input regular expressions. This is a port of AlignAssign.

Main Demo

Tips

Use only one \ when searching for literals.

# i.e.

# Use...
"[A-Z]+\s"

# ...instead of...
"[A-Z]+\\s"

# ...to search for a letter followed by a space.

Behavior of commented-out regular expressions

Be mindful that highling a chunk of code which has assignment operators within commented lines, like the following, and running the Align <- addin...

# This is a commented line with an assignment operator <-
a <- 1:5
b <- 6:10
c <- 11:15
# There is an assignment operator <- here, too

...will result in something like this.

# This is a commented line with an assignment operator <-
a                                                      <- 1:5
b                                                      <- 6:10
c                                                      <- 11:15
# There is an assignment operator                      <- here, too

Not so smart aligner

There is also no special handling of assignment operators within a function. So, if you highlighted the entire chunk below and then ran the Align <- addin...

var1 <- letters
var2 <- as.list(sample(1:26, 26))
names(var2) <- var1[unlist(var2)]
list.pos <- function(name, lst){
    matches <- sapply(name, function(x){
        matched <- which(names(lst) %in% x)

        if(length(matched) == 0) matched <- NA
        matched
    })
    return(matches)
}
positions <- list.pos(c("a", "bbb", "c"), var2)

...the result will look like this.

var1                                     <- letters
var2                                     <- as.list(sample(1:26, 26))
names(var2)                              <- var1[unlist(var2)]
list.pos                                 <- function(name, lst){
    matches                              <- sapply(name, function(x){
        matched                          <- which(names(lst) %in% x)

        if(length(matched) == 0) matched <- NA
        matched
    })
    return(matches)
}
positions                                <- list.pos(c("a", "bbb", "c"), var2)

Future Considerations

• Use shinyalert to handle cases where no regex match occurs, too few lines have been selected, and other errors and warnings that may occur.