feat(html): type and show function names in the language of the document

.gitignore

@@ -124,3 +124,4 @@ dist/
 wheelhouse/
 *.egg-info/
 .pytest_cache/
+/tools/formula/po/

CHANGELOG.md

@@ -33,6 +33,11 @@ The release run heads these entries with the version and opens a fresh
 
 ### Spreadsheets
 
+- The sheet editor takes a function name as LibreOffice shows it in the
+  language of the document, for example `SUMME` for `SUM` in a German one,
+  and opens a formula cell with those names. The file keeps the English
+  ones. The names come from LibreOffice's translations, for the 16
+  languages of the boolean words.
 - A recalculation and a save compute a cycle where the document iterates
   (`table:iteration` in an ods, `calcPr iterate` in an xlsx), as LibreOffice
   and Excel do: each group of cells that read each other, from what they

CMakeLists.txt

@@ -231,12 +231,14 @@ set(ODR_SOURCE_FILES
         "src/odr/internal/formula/formula_ast.cpp"
         "src/odr/internal/formula/formula_dependencies.cpp"
         "src/odr/internal/formula/formula_evaluator.cpp"
+        "src/odr/internal/formula/formula_function_names.cpp"
         "src/odr/internal/formula/formula_functions.cpp"
         "src/odr/internal/formula/formula_functions_date.cpp"
         "src/odr/internal/formula/formula_functions_logic.cpp"
         "src/odr/internal/formula/formula_functions_lookup.cpp"
         "src/odr/internal/formula/formula_functions_math.cpp"
         "src/odr/internal/formula/formula_functions_text.cpp"
+        "src/odr/internal/formula/formula_localize.cpp"
         "src/odr/internal/formula/formula_text.cpp"
         "src/odr/internal/formula/formula_parser.cpp"
         "src/odr/internal/formula/formula_value.cpp"

docs/design/spreadsheet-editing.md

@@ -132,9 +132,13 @@ as the decimal sign where that is the decimal sign of the locale. An array
 constant keeps the spelling of an `<f>`, `{1,2;3,4}`, in every locale. The
 module turns it into the syntax of the file, and the op states that:
 `{"type": "formula", "formula": "of:=SUM([.A1];[.B1])"}`. A formula cell opens
-on its formula, spelled the same way. A formula that does not parse refuses
-with `formulaInvalid`. Without the module, a formula refuses with
-`formulaInput`.
+on its formula, spelled the same way. A function name may be typed as
+LibreOffice shows it in the language of the document, `SUMME` for `SUM` in a
+German one, and a formula cell opens with those names
+(`formula::localized_functions`, from LibreOffice's translations by
+`tools/formula`). The match ignores the case of ASCII letters only. A formula
+that does not parse refuses with `formulaInvalid`. Without the module, a
+formula refuses with `formulaInput`.
 
 **Why:** the file states the type per cell (`office:value-type`, `c/@t`) and
 changes it freely, so a cell has no fixed type. A number cell writes
@@ -418,8 +422,6 @@ and the commits name. Git holds the full text of each decision.
 
 ## Open work
 
-- **Formula input.** Function names are the English ones, also where a
-  localized LibreOffice shows them translated.
 - **Out of the evaluator so far:** a dynamic array that the edit makes
   larger or smaller than the range the file states, a cell another document
   holds that its copy lacks, `INFO`, and localized function names. Each