1package chroma
 2
 3import "strings"
 4
 5// An Iterator across tokens.
 6//
 7// EOF will be returned at the end of the Token stream.
 8//
 9// If an error occurs within an Iterator, it may propagate this in a panic. Formatters should recover.
10type Iterator func() Token
11
12// Tokens consumes all tokens from the iterator and returns them as a slice.
13func (i Iterator) Tokens() []Token {
14	var out []Token
15	for t := i(); t != EOF; t = i() {
16		out = append(out, t)
17	}
18	return out
19}
20
21// Concaterator concatenates tokens from a series of iterators.
22func Concaterator(iterators ...Iterator) Iterator {
23	return func() Token {
24		for len(iterators) > 0 {
25			t := iterators[0]()
26			if t != EOF {
27				return t
28			}
29			iterators = iterators[1:]
30		}
31		return EOF
32	}
33}
34
35// Literator converts a sequence of literal Tokens into an Iterator.
36func Literator(tokens ...Token) Iterator {
37	return func() Token {
38		if len(tokens) == 0 {
39			return EOF
40		}
41		token := tokens[0]
42		tokens = tokens[1:]
43		return token
44	}
45}
46
47// SplitTokensIntoLines splits tokens containing newlines in two.
48func SplitTokensIntoLines(tokens []Token) (out [][]Token) {
49	var line []Token // nolint: prealloc
50	for _, token := range tokens {
51		for strings.Contains(token.Value, "\n") {
52			parts := strings.SplitAfterN(token.Value, "\n", 2)
53			// Token becomes the tail.
54			token.Value = parts[1]
55
56			// Append the head to the line and flush the line.
57			clone := token.Clone()
58			clone.Value = parts[0]
59			line = append(line, clone)
60			out = append(out, line)
61			line = nil
62		}
63		line = append(line, token)
64	}
65	if len(line) > 0 {
66		out = append(out, line)
67	}
68	// Strip empty trailing token line.
69	if len(out) > 0 {
70		last := out[len(out)-1]
71		if len(last) == 1 && last[0].Value == "" {
72			out = out[:len(out)-1]
73		}
74	}
75	return
76}