Forum OpenACS Q&A: proc like ns_getcsv for char delimited files?

What would be the reason for not using a standard csv format? One problem is generating the file. Just follow the rules specified at the link you provided. One nice feature of ns_getcsv is that it returns the number of fields found. If you want to enforce this for every row you can use a while:

while {[set fields [ns_getcsv $fileid csv_list]] == $len} ...

So I guess the answer is: no there isn't another proc like that, mostly because ns_getcsv needs to read char by char to understand the context of things like double quote, comma and new lines.

This works in the tcl interpreter environment:

proc ec_gets_tab_delimited_line {fileId varName} {
    set delimiter "\t"
    if {[eof $fileId]} {
        set return_val -1
    } else {
        gets $fileId line
        set varName [split $line $delimiter]
        set return_val [llength $varName]
    }
    return $return_val

Now to figure out how to format it for ad_proc so that the delimiter defaults to "\t" but can be changed.

ad_proc ec_gets_char_delimited_line {
    fileId
    varName
    {delimiter "\t"}
} {
    Reads and parses a line of data from a character delimited file 
    similar to ns_getscsv. Defaults to delimit tabs
} {
    if {[eof $fileId]} {
        set return_val -1
    } else {
        gets $fileId line
        set varName [split $line $delimiter]
        set return_val [llength $varName]
    }
    return $return_val
}

Does this appear in "good" form?

Thanks Alfred! I should check out the tcllib.

Thanks, Tom! Upvar was one of those strange reserved words, now is a friend =)

proc ec_gets_char_delimited_line {fileId varName {delimiter "\t"} } {
    upvar $varName split_line
    if {[eof $fileId]} {
        set return_val -1
        set split_line [list]
    } else {
        gets $fileId line
        set split_line [split $line $delimiter]
        set return_val [llength $split_line]
    }
    return $return_val
}

translating to ad_proc..

ad_proc ec_gets_char_delimited_line {
    fileId
    varName
    {delimiter "\t"}
} {
    Reads and parses a line of data from a character delimited file 
    similar to ns_getscsv. Defaults to delimit tabs
} {
    upvar $varName split_line
    if {[eof $fileId]} {
        set return_val -1
        set split_line [list]
    } else {
        gets $fileId line
        set split_line [split $line $delimiter]
        set return_val [llength $split_line]
    }
    return $return_val
}

Andrew it appears he has a much simpler format than even csv. ns_getcsv more than likely has to parse char by char to maintain state as it stumbles across the special characters that are actually content.

It isn't necessarily difficult, but I doubt it would be faster than ns_getcsv.