examples: add a Lorem Ipsum Generator (#26036)

Author: mike-ward

examples/lorem.v

@@ -0,0 +1,166 @@
+import rand
+import strings
+import flag
+import os
+
+// Features:
+// - All parameters configurable via flags
+// - Reproducible output via --seed
+// - No invalid punctuation sequences
+// - Em-dashes never near sentence edges
+
+// ---------------- Configuration ----------------
+
+pub struct LoremCfg {
+	paragraphs              int = 3
+	words_per_sentence      int = 10
+	sentences_per_paragraph int = 5
+	commas_per_sentence     int = 2
+	seed                    int
+}
+
+// ---------------- Generator --------------------
+
+pub fn generate_lorem(cfg LoremCfg) string {
+	lorem_words := ('lorem ipsum dolor sit amet consectetur adipiscing elit sed do eiusmod ' +
+		'tempor incididunt ut labore et dolore magna aliqua enim ad minim veniam ' +
+		'quis nostrud exercitation ullamco laboris nisi aliquip ex ea').split(' ')
+
+	comma_marks := ['‚', '،', '，', ',', '﹐']
+	sentence_marks := ['.', '…', '。', '!', '?']
+
+	if cfg.seed != 0 {
+		rand.seed([u32(cfg.seed), u32(cfg.seed ^ 0x9e3779b9)])
+	}
+
+	mut out := strings.new_builder(2048)
+
+	for p in 0 .. cfg.paragraphs {
+		sentence_count := vary(cfg.sentences_per_paragraph)
+
+		for _ in 0 .. sentence_count {
+			word_count := vary(cfg.words_per_sentence)
+
+			expected_breaks := if cfg.words_per_sentence > 0 {
+				(word_count * cfg.commas_per_sentence) / cfg.words_per_sentence
+			} else {
+				0
+			}
+
+			mut inserted_breaks := 0
+			mut last_had_splitter := false
+			min_dash_offset := 2
+
+			for w in 0 .. word_count {
+				word := lorem_words[rand.intn(lorem_words.len) or { 0 }]
+
+				if w == 0 {
+					out.write_string(capitalize(word))
+				} else {
+					out.write_string(' ')
+					out.write_string(word)
+				}
+
+				is_last := w == word_count - 1
+
+				// ---- Clause splitters
+				if !is_last && inserted_breaks < expected_breaks
+					&& (w + 1) * expected_breaks / word_count > inserted_breaks {
+					use_strong := rand.intn(6) or { 0 } == 0
+
+					if use_strong {
+						if w >= min_dash_offset && w < word_count - 1 - min_dash_offset {
+							out.write_string('—')
+						} else {
+							out.write_string(';')
+						}
+					} else {
+						out.write_string(comma_marks[rand.intn(comma_marks.len) or { 0 }])
+					}
+
+					inserted_breaks++
+					last_had_splitter = true
+					continue
+				}
+
+				last_had_splitter = false
+
+				// ---- Sentence terminator
+				if is_last {
+					if last_had_splitter {
+						out.write_string('.')
+					} else {
+						out.write_string(sentence_marks[rand.intn(sentence_marks.len) or { 0 }])
+					}
+				}
+			}
+
+			out.write_string(' ')
+		}
+
+		if p < cfg.paragraphs - 1 {
+			out.write_string('\n\n')
+		}
+	}
+
+	return out.str()
+}
+
+// ---------------- Utilities --------------------
+
+fn vary(base int) int {
+	if base <= 1 {
+		return 1
+	}
+	delta := base / 5
+	r := rand.intn(delta * 2 + 1) or { 0 }
+	return clamp(base + r - delta, 1, 10_000)
+}
+
+fn capitalize(s string) string {
+	if s.len == 0 {
+		return s
+	}
+	return s[..1].to_upper() + s[1..]
+}
+
+fn clamp(v int, min int, max int) int {
+	if v < min {
+		return min
+	}
+	if v > max {
+		return max
+	}
+	return v
+}
+
+// ---------------- CLI --------------------------
+
+fn main() {
+	mut fp := flag.new_flag_parser(os.args)
+	fp.application('lorem')
+	fp.description('Lorem Ipsum generator with structured punctuation')
+	fp.skip_executable()
+
+	paragraphs := fp.int('paragraphs', `p`, 3, 'number of paragraphs')
+	words := fp.int('words', `w`, 10, 'approx words per sentence')
+	sentences := fp.int('sentences', `s`, 5, 'approx sentences per paragraph')
+	commas := fp.int('commas', `c`, 2, 'comma density per sentence')
+	seed := fp.int('seed', 0, 0, 'RNG seed (0 = deterministic default)')
+
+	fp.finalize() or {
+		eprintln(err)
+		println(fp.usage())
+		return
+	}
+
+	cfg := LoremCfg{
+		paragraphs:              paragraphs
+		words_per_sentence:      words
+		sentences_per_paragraph: sentences
+		commas_per_sentence:     commas
+		seed:                    seed
+	}
+
+	println(generate_lorem(cfg))
+}