#Delimited text

Quoting and escaping come from the csv module (RFC 4180). This layer adds typing on read and formula-injection protection on write.

def wb as sheet.Workbook init sheet.readCsv(fs.readString("data.csv"), true);
fs.writeString("out.csv", sheet.writeCsv($wb, ""));

readDelimited(body, delimiter, typed) and writeDelimited(wb, sheetName, delimiter) take any one-character separator; TSV goes through the same code. A write takes one sheet, the first when sheetName is "". A read produces one sheet named CSV_SHEET_NAME ("Sheet1").

#Typing

With typed set, a field becomes a boolean, an error code, a number or an ISO date, tested in that order; anything else stays text:

sheet.readCsv("1,2.5,TRUE,2026-10-02,#N/A\n", true);
# number, number, bool, stamp, error

A number with a leading zero (007, 0123) stays text, since it is almost always an identifier. A plain 0 is a number. A field of only whitespace stays text. An empty field is an empty cell whether or not typed is set.

With typed false every field is text.

#Formula injection

A field that starts like a formula is executed by a spreadsheet application when someone opens the file (CWE-1236). For a file someone else will open, use writeCsvSafe, which prefixes those fields so they cannot execute:

fs.writeString("export.csv", sheet.writeCsvSafe($wb, ""));

writeCsv writes fields unchanged, so a file you read back yourself round-trips exactly.