func verifyProperties()

in cases/gen.go [522:628]
68 lines of code
37 McCabe index (conditional complexity)

func verifyProperties(chars []runeInfo) {
	for i, c := range chars {
		r := rune(i)

		// Rune properties.

		// A.1: modifier never changes on lowercase. [ltLower]
		if c.CCC > 0 && unicode.ToLower(r) != r {
			log.Fatalf("%U: non-starter changes when lowercased", r)
		}

		// A.2: properties of decompositions starting with I or J. [ltLower]
		d := norm.NFD.PropertiesString(string(r)).Decomposition()
		if len(d) > 0 {
			if d[0] == 'I' || d[0] == 'J' {
				// A.2.1: we expect at least an ASCII character and a modifier.
				if len(d) < 3 {
					log.Fatalf("%U: length of decomposition was %d; want >= 3", r, len(d))
				}

				// All subsequent runes are modifiers and all have the same CCC.
				runes := []rune(string(d[1:]))
				ccc := chars[runes[0]].CCC

				for _, mr := range runes[1:] {
					mc := chars[mr]

					// A.2.2: all modifiers have a CCC of Above or less.
					if ccc == 0 || ccc > above {
						log.Fatalf("%U: CCC of successive rune (%U) was %d; want (0,230]", r, mr, ccc)
					}

					// A.2.3: a sequence of modifiers all have the same CCC.
					if mc.CCC != ccc {
						log.Fatalf("%U: CCC of follow-up modifier (%U) was %d; want %d", r, mr, mc.CCC, ccc)
					}

					// A.2.4: for each trailing r, r in [0x300, 0x311] <=> CCC == Above.
					if (ccc == above) != (0x300 <= mr && mr <= 0x311) {
						log.Fatalf("%U: modifier %U in [U+0300, U+0311] != ccc(%U) == 230", r, mr, mr)
					}

					if i += len(string(mr)); i >= len(d) {
						break
					}
				}
			}
		}

		// A.3: no U+0307 in decomposition of Soft-Dotted rune. [ltUpper]
		if unicode.Is(unicode.Soft_Dotted, r) && strings.Contains(string(d), "\u0307") {
			log.Fatalf("%U: decomposition of soft-dotted rune may not contain U+0307", r)
		}

		// A.4: only rune U+0345 may be of CCC Iota_Subscript. [elUpper]
		if c.CCC == iotaSubscript && r != 0x0345 {
			log.Fatalf("%U: only rune U+0345 may have CCC Iota_Subscript", r)
		}

		// A.5: soft-dotted runes do not have exceptions.
		if c.SoftDotted && c.entry&exceptionBit != 0 {
			log.Fatalf("%U: soft-dotted has exception", r)
		}

		// A.6: Greek decomposition. [elUpper]
		if unicode.Is(unicode.Greek, r) {
			if b := norm.NFD.PropertiesString(string(r)).Decomposition(); b != nil {
				runes := []rune(string(b))
				// A.6.1: If a Greek rune decomposes and the first rune of the
				// decomposition is greater than U+00FF, the rune is always
				// great and not a modifier.
				if f := runes[0]; unicode.IsMark(f) || f > 0xFF && !unicode.Is(unicode.Greek, f) {
					log.Fatalf("%U: expected first rune of Greek decomposition to be letter, found %U", r, f)
				}
				// A.6.2: Any follow-up rune in a Greek decomposition is a
				// modifier of which the first should be gobbled in
				// decomposition.
				for _, m := range runes[1:] {
					switch m {
					case 0x0313, 0x0314, 0x0301, 0x0300, 0x0306, 0x0342, 0x0308, 0x0304, 0x345:
					default:
						log.Fatalf("%U: modifier %U is outside of expected Greek modifier set", r, m)
					}
				}
			}
		}

		// Breaking properties.

		// B.1: all runes with CCC > 0 are of break type Extend.
		if c.CCC > 0 && c.BreakType != "Extend" {
			log.Fatalf("%U: CCC == %d, but got break type %s; want Extend", r, c.CCC, c.BreakType)
		}

		// B.2: all cased runes with c.CCC == 0 are of break type ALetter.
		if c.CCC == 0 && c.Cased && c.BreakType != "ALetter" {
			log.Fatalf("%U: cased, but got break type %s; want ALetter", r, c.BreakType)
		}

		// B.3: letter category.
		if c.CCC == 0 && c.BreakCat != breakBreak && !c.CaseIgnorable {
			if c.BreakCat != breakLetter {
				log.Fatalf("%U: check for letter break type gave %d; want %d", r, c.BreakCat, breakLetter)
			}
		}
	}
}