| 1 | package calc |
| 2 | |
| 3 | // fn_math.go: SUM, AVERAGE, COUNT, COUNTA, MIN, MAX — the aggregate |
| 4 | // family. Rounding/misc math (ROUND, ROUNDUP, ROUNDDOWN, ABS, SQRT, |
| 5 | // POWER, MOD) lives in fn_math_round.go; split out to stay under the |
| 6 | // 300-line cap once this file grew the literal-vs-reference machinery |
| 7 | // below. |
| 8 | |
| 9 | func init() { |
| 10 | registerNode("SUM", fnSum) |
| 11 | registerNode("AVERAGE", fnAverage) |
| 12 | registerNode("COUNT", fnCount) |
| 13 | Register("COUNTA", fnCounta) |
| 14 | registerNode("MIN", fnMin) |
| 15 | registerNode("MAX", fnMax) |
| 16 | } |
| 17 | |
| 18 | // taggedValue pairs a value with whether it came from a cell reference — |
| 19 | // a bare *Ref, or one of a *Range's flattened cells — rather than being |
| 20 | // typed directly into the formula. SUM, AVERAGE, COUNT, MIN and MAX all |
| 21 | // need this distinction: Excel silently ignores a blank, text, or |
| 22 | // logical value read FROM a reference, but coerces (or errors on) that |
| 23 | // same kind of value when it is typed DIRECTLY as an argument — |
| 24 | // SUM(A1) where A1 contains TRUE is 0, but SUM(TRUE) is 1. Microsoft's |
| 25 | // own documentation for SUM/AVERAGE/COUNT/MIN/MAX all use the same |
| 26 | // phrase for the direct-argument case: "logical values and text |
| 27 | // representations of numbers that you type directly into the list of |
| 28 | // arguments are counted." |
| 29 | // |
| 30 | // This is why these five register as nodeFuncs (registry.go) instead of |
| 31 | // ordinary Funcs: by the time an ordinary Func sees a flattened |
| 32 | // []Value, a reference's cells and a literal argument are |
| 33 | // indistinguishable — the exact gap flagged, but not yet closed, the |
| 34 | // first time this file was written. |
| 35 | type taggedValue struct { |
| 36 | Value |
| 37 | fromRef bool |
| 38 | } |
| 39 | |
| 40 | // evalAggArgs evaluates a call's argument nodes into taggedValues. A bare |
| 41 | // *Ref and each cell of a *Range are both tagged fromRef=true — Excel |
| 42 | // treats a single-cell reference the same as a one-cell range for this |
| 43 | // purpose, not like a literal. Everything else (a number/string/bool |
| 44 | // literal, or any computed expression such as an arithmetic operation or |
| 45 | // a nested call) evaluates through Eval and is tagged fromRef=false. |
| 46 | func evalAggArgs(nodes []Node, env Env) []taggedValue { |
| 47 | var out []taggedValue |
| 48 | for _, n := range nodes { |
| 49 | switch t := n.(type) { |
| 50 | case *Range: |
| 51 | cells, ok := rangeCells(t) |
| 52 | if !ok { |
| 53 | out = append(out, taggedValue{Value{Kind: KindErr, Err: ErrRef}, true}) |
| 54 | continue |
| 55 | } |
| 56 | for _, k := range cells { |
| 57 | out = append(out, taggedValue{env.CellValue(k), true}) |
| 58 | } |
| 59 | case *Ref: |
| 60 | out = append(out, taggedValue{env.CellValue(refKey(t)), true}) |
| 61 | default: |
| 62 | out = append(out, taggedValue{Eval(n, env), false}) |
| 63 | } |
| 64 | } |
| 65 | return out |
| 66 | } |
| 67 | |
| 68 | // numericValues applies to SUM, AVERAGE, MIN and MAX. Any KindErr value |
| 69 | // propagates immediately, left-most wins — matching every other error |
| 70 | // path in this package. A value read from a reference (fromRef=true) |
| 71 | // counts only if it is already KindNum: a blank, a text cell, or a |
| 72 | // logical cell is silently skipped, matching how Excel treats a range's |
| 73 | // own blank/text/logical cells. A value typed directly as an argument |
| 74 | // (fromRef=false) additionally coerces a KindBool to 1/0 and a KindStr |
| 75 | // that parses as a number — Excel's own "typed directly into the list of |
| 76 | // arguments" rule (see taggedValue's doc comment). A literal string that |
| 77 | // does NOT parse as a number is #VALUE! — unlike a range's text cell, a |
| 78 | // literal you plainly meant to be numeric is not silently ignored. |
| 79 | func numericValues(args []taggedValue) ([]float64, *Value) { |
| 80 | var nums []float64 |
| 81 | for i := range args { |
| 82 | a := args[i] |
| 83 | if a.Kind == KindErr { |
| 84 | v := a.Value |
| 85 | return nil, &v |
| 86 | } |
| 87 | if a.fromRef { |
| 88 | if a.Kind == KindNum { |
| 89 | nums = append(nums, a.Num) |
| 90 | } |
| 91 | continue |
| 92 | } |
| 93 | switch a.Kind { |
| 94 | case KindNum: |
| 95 | nums = append(nums, a.Num) |
| 96 | case KindBool: |
| 97 | if a.Bool { |
| 98 | nums = append(nums, 1) |
| 99 | } else { |
| 100 | nums = append(nums, 0) |
| 101 | } |
| 102 | case KindStr: |
| 103 | n, ek := toNumber(a.Value) |
| 104 | if ek != ErrNone { |
| 105 | v := errValue(ErrValue) |
| 106 | return nil, &v |
| 107 | } |
| 108 | nums = append(nums, n) |
| 109 | default: |
| 110 | // KindEmpty typed directly: unreachable in practice — the |
| 111 | // only source of KindEmpty is an untouched cell, and every |
| 112 | // cell-reference path is already tagged fromRef=true above |
| 113 | // (evalAggArgs) — kept only for defensiveness. |
| 114 | } |
| 115 | } |
| 116 | return nums, nil |
| 117 | } |
| 118 | |
| 119 | func fnSum(argNodes []Node, env Env) Value { |
| 120 | nums, errv := numericValues(evalAggArgs(argNodes, env)) |
| 121 | if errv != nil { |
| 122 | return *errv |
| 123 | } |
| 124 | var total float64 |
| 125 | for _, n := range nums { |
| 126 | total += n |
| 127 | } |
| 128 | return Value{Kind: KindNum, Num: total} |
| 129 | } |
| 130 | |
| 131 | func fnAverage(argNodes []Node, env Env) Value { |
| 132 | nums, errv := numericValues(evalAggArgs(argNodes, env)) |
| 133 | if errv != nil { |
| 134 | return *errv |
| 135 | } |
| 136 | if len(nums) == 0 { |
| 137 | return errValue(ErrDiv0) |
| 138 | } |
| 139 | var total float64 |
| 140 | for _, n := range nums { |
| 141 | total += n |
| 142 | } |
| 143 | return Value{Kind: KindNum, Num: total / float64(len(nums))} |
| 144 | } |
| 145 | |
| 146 | // fnCount counts numeric values: a KindNum from anywhere, plus — per |
| 147 | // numericValues' doc comment on the same literal-vs-reference |
| 148 | // distinction — a KindBool or a numeric-looking KindStr typed DIRECTLY |
| 149 | // as an argument (COUNT(1,2,"a",TRUE) is 3: "a" doesn't parse as a |
| 150 | // number and is skipped, but TRUE does count because it was typed |
| 151 | // directly, not read from a reference). Unlike SUM/AVERAGE/MIN/MAX, no |
| 152 | // argument here propagates an error — COUNT is a tally, and a broken |
| 153 | // cell elsewhere in a range is common enough (a VLOOKUP helper column |
| 154 | // full of #N/A, say) that COUNT/COUNTA are relied on to scan past it |
| 155 | // rather than becoming it. |
| 156 | func fnCount(argNodes []Node, env Env) Value { |
| 157 | n := 0 |
| 158 | for _, a := range evalAggArgs(argNodes, env) { |
| 159 | if a.Kind == KindErr { |
| 160 | continue |
| 161 | } |
| 162 | if a.fromRef { |
| 163 | if a.Kind == KindNum { |
| 164 | n++ |
| 165 | } |
| 166 | continue |
| 167 | } |
| 168 | switch a.Kind { |
| 169 | case KindNum, KindBool: |
| 170 | n++ |
| 171 | case KindStr: |
| 172 | if _, ek := toNumber(a.Value); ek == ErrNone { |
| 173 | n++ |
| 174 | } |
| 175 | } |
| 176 | } |
| 177 | return Value{Kind: KindNum, Num: float64(n)} |
| 178 | } |
| 179 | |
| 180 | // fnCounta counts every argument that is not KindEmpty — numbers, |
| 181 | // strings, booleans and errors all count as "present," from either a |
| 182 | // reference or a literal alike, which is why (unlike its four siblings |
| 183 | // above) COUNTA needs no literal-vs-reference distinction and stays an |
| 184 | // ordinary Func. This is the property COUNT vs. COUNTA hinges on (task |
| 185 | // 8's brief names it directly): neither counts a blank cell, but COUNTA |
| 186 | // counts everything else that COUNT would skip. |
| 187 | func fnCounta(args []Value) Value { |
| 188 | n := 0 |
| 189 | for _, a := range args { |
| 190 | if a.Kind != KindEmpty { |
| 191 | n++ |
| 192 | } |
| 193 | } |
| 194 | return Value{Kind: KindNum, Num: float64(n)} |
| 195 | } |
| 196 | |
| 197 | func fnMin(argNodes []Node, env Env) Value { |
| 198 | nums, errv := numericValues(evalAggArgs(argNodes, env)) |
| 199 | if errv != nil { |
| 200 | return *errv |
| 201 | } |
| 202 | if len(nums) == 0 { |
| 203 | return Value{Kind: KindNum, Num: 0} |
| 204 | } |
| 205 | m := nums[0] |
| 206 | for _, n := range nums[1:] { |
| 207 | if n < m { |
| 208 | m = n |
| 209 | } |
| 210 | } |
| 211 | return Value{Kind: KindNum, Num: m} |
| 212 | } |
| 213 | |
| 214 | func fnMax(argNodes []Node, env Env) Value { |
| 215 | nums, errv := numericValues(evalAggArgs(argNodes, env)) |
| 216 | if errv != nil { |
| 217 | return *errv |
| 218 | } |
| 219 | if len(nums) == 0 { |
| 220 | return Value{Kind: KindNum, Num: 0} |
| 221 | } |
| 222 | m := nums[0] |
| 223 | for _, n := range nums[1:] { |
| 224 | if n > m { |
| 225 | m = n |
| 226 | } |
| 227 | } |
| 228 | return Value{Kind: KindNum, Num: m} |
| 229 | } |
| 230 | |
amadan