| 1 | package calc |
| 2 | |
| 3 | import "strings" |
| 4 | |
| 5 | func init() { |
| 6 | Register("CONCAT", fnConcat) |
| 7 | Register("LEFT", fnLeft) |
| 8 | Register("RIGHT", fnRight) |
| 9 | Register("MID", fnMid) |
| 10 | Register("LEN", fnLen) |
| 11 | Register("TRIM", fnTrim) |
| 12 | Register("UPPER", fnUpper) |
| 13 | Register("LOWER", fnLower) |
| 14 | } |
| 15 | |
| 16 | func fnConcat(args []Value) Value { |
| 17 | var sb strings.Builder |
| 18 | for _, a := range args { |
| 19 | if a.Kind == KindErr { |
| 20 | return a |
| 21 | } |
| 22 | sb.WriteString(toStr(a)) |
| 23 | } |
| 24 | return Value{Kind: KindStr, Str: sb.String()} |
| 25 | } |
| 26 | |
| 27 | // textAndCount pulls the (text, count) shape shared by LEFT and RIGHT: |
| 28 | // text is required, count defaults to defaultCount and, when given, must |
| 29 | // coerce to a non-negative integer. |
| 30 | func textAndCount(args []Value, defaultCount int) (text string, count int, errv Value, ok bool) { |
| 31 | if len(args) < 1 || len(args) > 2 { |
| 32 | return "", 0, errValue(ErrValue), false |
| 33 | } |
| 34 | if args[0].Kind == KindErr { |
| 35 | return "", 0, args[0], false |
| 36 | } |
| 37 | text = toStr(args[0]) |
| 38 | count = defaultCount |
| 39 | if len(args) == 2 { |
| 40 | if args[1].Kind == KindErr { |
| 41 | return "", 0, args[1], false |
| 42 | } |
| 43 | n, ek := toNumber(args[1]) |
| 44 | if ek != ErrNone { |
| 45 | return "", 0, errValue(ek), false |
| 46 | } |
| 47 | count = int(n) |
| 48 | } |
| 49 | if count < 0 { |
| 50 | return "", 0, errValue(ErrValue), false |
| 51 | } |
| 52 | return text, count, Value{}, true |
| 53 | } |
| 54 | |
| 55 | // fnLeft and fnRight operate on runes, not bytes, so a multi-byte |
| 56 | // character counts as one character the way Excel's own LEN/LEFT/RIGHT |
| 57 | // do (their unit is "character," not "byte"). |
| 58 | func fnLeft(args []Value) Value { |
| 59 | text, n, errv, ok := textAndCount(args, 1) |
| 60 | if !ok { |
| 61 | return errv |
| 62 | } |
| 63 | r := []rune(text) |
| 64 | if n > len(r) { |
| 65 | n = len(r) |
| 66 | } |
| 67 | return Value{Kind: KindStr, Str: string(r[:n])} |
| 68 | } |
| 69 | |
| 70 | func fnRight(args []Value) Value { |
| 71 | text, n, errv, ok := textAndCount(args, 1) |
| 72 | if !ok { |
| 73 | return errv |
| 74 | } |
| 75 | r := []rune(text) |
| 76 | if n > len(r) { |
| 77 | n = len(r) |
| 78 | } |
| 79 | return Value{Kind: KindStr, Str: string(r[len(r)-n:])} |
| 80 | } |
| 81 | |
| 82 | // fnMid implements MID(text, start_num, num_chars): start_num is |
| 83 | // 1-based, per Excel; a start past the end of text returns "" rather |
| 84 | // than an error, matching Excel. |
| 85 | func fnMid(args []Value) Value { |
| 86 | if len(args) != 3 { |
| 87 | return errValue(ErrValue) |
| 88 | } |
| 89 | if args[0].Kind == KindErr { |
| 90 | return args[0] |
| 91 | } |
| 92 | if args[1].Kind == KindErr { |
| 93 | return args[1] |
| 94 | } |
| 95 | if args[2].Kind == KindErr { |
| 96 | return args[2] |
| 97 | } |
| 98 | text := toStr(args[0]) |
| 99 | startF, ek := toNumber(args[1]) |
| 100 | if ek != ErrNone { |
| 101 | return errValue(ek) |
| 102 | } |
| 103 | countF, ek := toNumber(args[2]) |
| 104 | if ek != ErrNone { |
| 105 | return errValue(ek) |
| 106 | } |
| 107 | start, count := int(startF), int(countF) |
| 108 | if start < 1 || count < 0 { |
| 109 | return errValue(ErrValue) |
| 110 | } |
| 111 | r := []rune(text) |
| 112 | if start > len(r) { |
| 113 | return Value{Kind: KindStr, Str: ""} |
| 114 | } |
| 115 | end := start - 1 + count |
| 116 | if end > len(r) { |
| 117 | end = len(r) |
| 118 | } |
| 119 | return Value{Kind: KindStr, Str: string(r[start-1 : end])} |
| 120 | } |
| 121 | |
| 122 | func fnLen(args []Value) Value { |
| 123 | if len(args) != 1 { |
| 124 | return errValue(ErrValue) |
| 125 | } |
| 126 | if args[0].Kind == KindErr { |
| 127 | return args[0] |
| 128 | } |
| 129 | return Value{Kind: KindNum, Num: float64(len([]rune(toStr(args[0]))))} |
| 130 | } |
| 131 | |
| 132 | // fnTrim collapses runs of whitespace to a single space and strips |
| 133 | // leading/trailing whitespace, via strings.Fields — slightly broader |
| 134 | // than Excel's own TRIM (which targets the plain ASCII space character |
| 135 | // specifically, not tabs or newlines); close enough for this task's |
| 136 | // scope, and flagged here rather than left to be discovered as a silent |
| 137 | // divergence. |
| 138 | func fnTrim(args []Value) Value { |
| 139 | if len(args) != 1 { |
| 140 | return errValue(ErrValue) |
| 141 | } |
| 142 | if args[0].Kind == KindErr { |
| 143 | return args[0] |
| 144 | } |
| 145 | return Value{Kind: KindStr, Str: strings.Join(strings.Fields(toStr(args[0])), " ")} |
| 146 | } |
| 147 | |
| 148 | func fnUpper(args []Value) Value { |
| 149 | if len(args) != 1 { |
| 150 | return errValue(ErrValue) |
| 151 | } |
| 152 | if args[0].Kind == KindErr { |
| 153 | return args[0] |
| 154 | } |
| 155 | return Value{Kind: KindStr, Str: strings.ToUpper(toStr(args[0]))} |
| 156 | } |
| 157 | |
| 158 | func fnLower(args []Value) Value { |
| 159 | if len(args) != 1 { |
| 160 | return errValue(ErrValue) |
| 161 | } |
| 162 | if args[0].Kind == KindErr { |
| 163 | return args[0] |
| 164 | } |
| 165 | return Value{Kind: KindStr, Str: strings.ToLower(toStr(args[0]))} |
| 166 | } |
| 167 | |
amadan