| 1 | package sheets |
| 2 | |
| 3 | import ( |
| 4 | "strings" |
| 5 | |
| 6 | "amadan.net/oficina/sheets/internal/sheets/calc" |
| 7 | ) |
| 8 | |
| 9 | // Copy and fill: spec §4.2's translation pass. |
| 10 | // |
| 11 | // > **Copy / drag-fill** — Translation pass at paste time. Relative refs |
| 12 | // > are re-resolved by offset from the paste anchor; absolute (`$A$1`) |
| 13 | // > refs resolve to the same id. Unavoidable — it is what relative |
| 14 | // > means. |
| 15 | // |
| 16 | // This is the pass stable row and column identity does NOT remove, and |
| 17 | // the spec says so in the same paragraph. calc.Translate has existed |
| 18 | // since the engine landed and had no caller until now, so filling |
| 19 | // `=A1*2` down a column wrote `=A1*2` into every cell: the grid showed |
| 20 | // the same number three times and nothing in the suite disagreed, |
| 21 | // because every test wrote a cell rather than copying one. |
| 22 | // |
| 23 | // The offset arrives on the cell write itself rather than through a |
| 24 | // route of its own. A paste is n cell writes, each of which already |
| 25 | // carries its destination; naming the cell it came from is one more |
| 26 | // field on a body that is already explicit and already allowlisted, and |
| 27 | // it keeps one code path for "a cell changed" rather than two that can |
| 28 | // disagree about sealing, versioning or fan-out. |
| 29 | |
| 30 | // translateCopied rewrites a copied cell's raw input for its new home. |
| 31 | // |
| 32 | // dRow and dCol are the destination minus the origin. Everything that |
| 33 | // is not a formula comes back untouched — a text cell reading "A1 and |
| 34 | // B2" is not a reference and rewriting it would corrupt the one kind of |
| 35 | // cell that cannot need this. |
| 36 | // |
| 37 | // A formula that will not parse also comes back untouched, which is |
| 38 | // deliberate: the write then fails exactly as it would have if the same |
| 39 | // text had been typed, rather than failing differently because it |
| 40 | // arrived by paste. |
| 41 | func translateCopied(raw string, dRow, dCol int) string { |
| 42 | if dRow == 0 && dCol == 0 { |
| 43 | return raw |
| 44 | } |
| 45 | if !strings.HasPrefix(raw, "=") { |
| 46 | return raw |
| 47 | } |
| 48 | n, err := calc.Parse(raw[1:]) |
| 49 | if err != nil { |
| 50 | return raw |
| 51 | } |
| 52 | out, ok := calc.TranslateChecked(n, dRow, dCol) |
| 53 | if !ok { |
| 54 | // Off the top or the left of the grid. Excel writes #REF! and so |
| 55 | // do we, as LITERAL TEXT and not as an error value: calc's parser |
| 56 | // has no error literal, so there is no formula source that |
| 57 | // evaluates to calc.ErrRef, and inventing one is a change to the |
| 58 | // grammar rather than to this function. |
| 59 | // |
| 60 | // The difference is real and worth knowing: =SUM() over a cell |
| 61 | // holding the text "#REF!" treats it as text, where Excel would |
| 62 | // propagate the error. It is visible to the person either way, |
| 63 | // which is the property that matters most here, and the cell is |
| 64 | // written rather than skipped — a paste that silently drops a |
| 65 | // cell is the failure this whole change exists to remove. |
| 66 | return calc.ErrRef.String() |
| 67 | } |
| 68 | return "=" + calc.Render(out) |
| 69 | } |
| 70 | |
amadan