Expand tab characters in one line of text to spaces

The PDF graphics device cannot measure or render the tab glyph (0x09): it warns "font width unknown" and treats the tab as zero width, so a tab in cell or page text would silently collapse. Tabs are therefore expanded to spaces before any measuring or drawing.

Usage

.convert_tabs(s, ..., tab_indent_spaces = 2L, tab_infix_spaces = 1L)

Arguments

s

A single character string with no embedded newline.

...

Ignored.

tab_indent_spaces

Number of spaces a leading (indentation) tab — one preceded only by whitespace — is expanded to. Default 2, matching the common "a tab indents by two spaces" convention.

tab_infix_spaces

Number of spaces an in-line tab — one with non-whitespace to its left — is expanded to. Default 1; the resulting space then behaves as an ordinary breakable space.

Value

s with tab characters replaced by spaces. Strings containing no tab are returned untouched (fast path).