doc update/command synopses

assets/disk0/tvdos/bin/synopsis.js

@@ -0,0 +1,180 @@
+/*
+ * synopsis.js -- system-wide help / tldr.
+ *
+ * Prints a command's human-targeted one-line summary and an auto-generated
+ * synopsis (usage line, arguments, options and constraints) derived from its
+ * TSF .synopsis document via the `synopsis` library (synopsis.mjs).
+ *
+ * Usage: synopsis PROGRAM
+ *        synopsis            (describes itself)
+ */
+
+let syn
+try {
+    syn = require("synopsis")
+} catch (e) {
+    printerrln("synopsis: the 'synopsis' library is not installed")
+    return 1
+}
+
+const termW = (con.getmaxyx()[1]) || 80
+
+// Word-wrap plain text to `width`, returning an array of lines.
+function wrap(text, width) {
+    if (!text) return []
+    if (width < 8) width = 8
+    let words = ('' + text).split(/\s+/).filter(function (w) { return w.length })
+    let lines = [], line = ''
+    words.forEach(function (w) {
+        if (line.length === 0) line = w
+        else if (line.length + 1 + w.length <= width) line += ' ' + w
+        else { lines.push(line); line = w }
+    })
+    if (line.length) lines.push(line)
+    return lines
+}
+
+// Print a "left  summary" row: the summary is wrapped into the right column and
+// continuation lines are aligned under it. An over-wide `left` spills onto its
+// own line.
+function row(left, summary, leftW, indent) {
+    let pad = ' '.repeat(indent)
+    let gap = 2
+    let sumW = Math.max(8, termW - indent - leftW - gap)
+    let wrapped = wrap(summary, sumW)
+    if (left.length > leftW) {
+        println(pad + left)
+        wrapped.forEach(function (l) { println(pad + ' '.repeat(leftW + gap) + l) })
+    } else {
+        let first = wrapped.length ? wrapped[0] : ''
+        println(pad + left + ' '.repeat(leftW - left.length + gap) + first)
+        for (let i = 1; i < wrapped.length; i++)
+            println(pad + ' '.repeat(leftW + gap) + wrapped[i])
+    }
+}
+
+// ---- resolve the target ----------------------------------------------------
+let token = (exec_args[1] !== undefined && exec_args[1] !== '') ? exec_args[1] : "synopsis"
+
+let model = syn.getModel(token)
+if (!model) {
+    printerrln(`synopsis: no synopsis found for '${token}'`)
+    return 1
+}
+
+// Display name for a referenced symbol id (used by the constraints section).
+function symDisplay(id) {
+    let s = model.symbols[id]
+    if (!s) return id
+    if (s.kind === 'option')     return s.long || s.short || id
+    if (s.kind === 'positional') return s.name || id
+    if (s.kind === 'subcommand') return s.name || id
+    return id
+}
+
+// Append a "{a, b, c}" hint of permitted values to a summary, if any.
+function withValues(summary, values) {
+    if (!values || !values.length) return summary || ''
+    let vs = values.map(function (v) {
+        return (v && typeof v === 'object' && ('value' in v)) ? v.value : v
+    }).join(', ')
+    return (summary ? summary + '  ' : '') + '{' + vs + '}'
+}
+
+// Left-column text for an option, e.g. "-o, --output=FILE".
+function optionLeft(e) {
+    let forms = []
+    if (e.short) forms.push(e.short)
+    if (e.long)  forms.push(e.long)
+    let s = forms.join(', ')
+    if (e.hasValue) {
+        let vn = (e.value && (e.value.name || e.value.type)) || 'VALUE'
+        if (e.long) s += e.valueRequired ? '=' + vn : '[=' + vn + ']'
+        else        s += e.valueRequired ? ' ' + vn : ' [' + vn + ']'
+    }
+    return s
+}
+function optionSummary(e) {
+    let s = e.summary || ''
+    if (e.negatable) s += (s ? ' ' : '') + '(negatable)'
+    if (e.value && e.value.values && e.value.values.length) s = withValues(s, e.value.values)
+    return s
+}
+
+function constraintText(c) {
+    let names = (c.symbols || []).map(symDisplay)
+    if (c.type === 'conflicts')  return 'Mutually exclusive: ' + names.join(', ')
+    if (c.type === 'requires')   return symDisplay(c.subject) + ' requires ' + (c.targets || []).map(symDisplay).join(', ')
+    if (c.type === 'implies')    return symDisplay(c.subject) + ' implies ' + (c.targets || []).map(symDisplay).join(', ')
+    if (c.type === 'cardinality') {
+        let mn = c.minimum, mx = c.maximum, q
+        if (mn === 1 && mx === 1) q = 'Exactly one of'
+        else if (mn === 1 && mx === undefined) q = 'At least one of'
+        else if (mn === undefined && mx === 1) q = 'At most one of'
+        else q = `Between ${mn} and ${mx} of`
+        return q + ': ' + names.join(', ')
+    }
+    return null
+}
+
+// ---- gather rows -----------------------------------------------------------
+let argEntries = model.positionals.map(function (p) {
+    return { left: (p.name || p.id) + (p.repeatable ? '...' : ''), summary: withValues(p.summary, p.values) }
+})
+let optEntries = model.flags.map(function (e) {
+    return { left: optionLeft(e), summary: optionSummary(e) }
+})
+let subEntries = model.subcommands.map(function (s) {
+    return { left: s.name, summary: s.summary || '' }
+})
+
+// shared left-column width (capped so a long flag does not push everything out)
+let leftW = 4
+argEntries.concat(optEntries, subEntries).forEach(function (e) { if (e.left.length > leftW) leftW = e.left.length })
+if (leftW > 30) leftW = 30
+
+// ---- render ----------------------------------------------------------------
+let title = model.name || token
+println(model.summary ? `${title} - ${model.summary}` : title)
+println()
+
+let usage = syn.getUsage(token)
+if (usage) {
+    println("Usage:")
+    println("    " + usage)
+    println()
+}
+
+if (model.description) {
+    wrap(model.description, termW).forEach(function (l) { println(l) })
+    println()
+}
+
+if (subEntries.length) {
+    println("Commands:")
+    subEntries.forEach(function (e) { row(e.left, e.summary, leftW, 4) })
+    println()
+}
+
+if (argEntries.length) {
+    println("Arguments:")
+    argEntries.forEach(function (e) { row(e.left, e.summary, leftW, 4) })
+    println()
+}
+
+if (optEntries.length) {
+    println("Options:")
+    optEntries.forEach(function (e) { row(e.left, e.summary, leftW, 4) })
+    println()
+}
+
+if (model.constraints && model.constraints.length) {
+    let lines = model.constraints.map(constraintText).filter(function (t) { return t })
+    if (lines.length) {
+        println("Constraints:")
+        lines.forEach(function (l) { println("    " + l) })
+        println()
+    }
+}
+
+return 0