text.bend source

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# Pure terminal text: ANSI SGR styling and Unicode 17 display width.import Baseimport 0x6c784a08486e2e02415e89c5249e9e8a/unicode.bend as Unicodeimport ./width.bend as W# Wrap text in one numeric SGR code and a reset when enabled; otherwise return it unchanged.def style(enabled: Bool, code: U32, text: String) -> String:  match enabled:    case True{}:      String.concat(["\u{1B}[", U32.show(code), "m", text, "\u{1B}[0m"])    case False{}:      textdef vs16(s: String) -> Bool:  match s:    case SNil{}:      False{}    case SCon{Chr{+c}, t}:      U32.is_eq(c, 65039) || vs16(t)# A grapheme cluster takes its first code point's columns (W.w); VS16 makes a narrow base an emoji, 2 wide.def cluster(g: String) -> U32:  match g:    case SNil{}:      0    case SCon{Chr{+c}, t}:      +w = W.w(c)      Bool.pick(U32, U32.is_eq(w, 1) && vs16(t), 2, w)def width.go(gs: List<&2, String>, +acc: U32) -> U32:  match gs:    case Nil{}:      acc    case Con{g, t}:      width.go(t, (acc + cluster(g) : U32))# Display columns: East Asian Wide and Fullwidth clusters are 2, marks and controls 0, Ambiguous 1.# Escape sequences are not stripped: style()'s output is wider than what the terminal shows.def width(text: String) -> U32:  width.go(Unicode.graphemes(text), 0)# Append spaces until text occupies at least cols display columns.def pad_right(+text: String, +cols: U32) -> String:  +w = width(text)  +n = Bool.pick(U32, U32.is_lt(w, cols), (cols - w : U32), 0)  String.append(text, String.repeat(" ", U32.to_nat(n)))