NEWS.md

writexl 2.0.1

A compiled-code cleanup requested by CRAN; nothing changes at the R level.

• The bundled libxlsxwriter assigned the result of strstr()/strpbrk() on a const string to a non-const pointer in four places. With GCC 16 and glibc 2.43, where the C23 <string.h> search functions preserve const, those assignments drew "discards 'const' qualifier" warnings, and the CRAN checks on the r-devel Fedora flavors flag them as significant. The pointers were only ever read, and are now const (or gone).

writexl 2.0.0

writexl is now maintained by Bill Denney; Jeroen Ooms remains an author.

Breaking changes

The version number is 2.0.0 for these, each of which can change what an existing script writes. Everything else in this release is additive.

• POSIXct columns are no longer silently converted to UTC. When every datetime in the workbook shares one time zone, the zone is dropped and local wall-clock time is written; when they differ, all are converted to UTC with a warning. Code that relied on always getting the UTC instant will see shifted values.

• Date values before 1900-03-01 were written one day too late, and now agree with POSIXct. Files written earlier that contain such dates disagree with files written now.

• Columns of a type writexl cannot represent (complex, raw, a bare list column) are an error naming the column, where before they warned and wrote empty cells. A script that ignored the warning now stops.

• Sheet names are repaired differently: truncated to a genuine 31 characters rather than 29, with characters Excel forbids replaced and the resulting duplicates resolved. A workbook with long or awkward sheet names may end up with different tab names than before -- and, in the "2024/Q1" case, one Excel will actually open.

• A cell column has no column-wide notion of "these are all formulas", so df[i, j] <- "=SUM(A1:A2)" writes the eleven characters rather than a formula, and warns that it has. xl_formula() returned a classed character vector in 1.5.4 and the class survived a row assignment, which is what made the older spelling work; it now returns a cell object, where a formula is a property of each cell. Build the column and mark it once:

  NOTES[[2]] <- xl_formula(NOTES[[2]])   # after the rows are filled in

• xl_hyperlink(name = ) is deprecated in favour of value, which now occupies the position name used to, so positional calls are unaffected. Supplying name warns; supplying both is an error.

New features

writexl now reaches the whole feature set of the libxlsxwriter it bundles. Each entry below names the one or two functions to start from; the vignettes carry the detail.

• Cell content — xl_cell_general() writes any combination of value, formula, hyperlink, format and comment, in mixed-type columns. It also carries array and dynamic array formulas, comments (xl_comment()) and rich strings, one cell in several fonts (xl_rich_string()). xl_formula() and xl_hyperlink() return these objects and stay backward compatible; xl_hyperlink() now writes a real URL hyperlink, with display text and a tooltip.

• Formatting — xl_format() and the group constructors xl_font(), xl_fill(), xl_border(), xl_align(), xl_num_format() and xl_protection() build reusable format objects that combine with +, and apply to a cell, a column, a row, a sheet or the workbook.

• Conditional formatting — xl_sheet(conditional =), with xl_cond_cell() pairing a rule with a format and xl_cond_scale(), xl_cond_bar() and xl_cond_icons() for colour scales, data bars and icon sets.

• Data validation — xl_sheet(validation = xl_validation(...)): dropdown lists, numeric, date, time and text-length bounds, and custom formulas, with the input and error messages Excel shows (#43).

• Autofilters — xl_sheet(filter = xl_filter(...)). Excel does not apply a filter when a file is opened, so writexl also hides the rows the criteria exclude; without that the sheet looks filtered but shows every row. xl_filter_keep() exposes the same matching rule on its own. The rules reproduce Excel's, which were measured rather than assumed.

• Worksheets and workbooks — xl_sheet() carries column and row geometry (in Excel's units or in pixels), frozen and split panes, gridlines, tab state and the opening view, protection, outline display (xl_outline()), and the error indicators Excel shows on cells it believes are wrong. xl_workbook() and xl_properties() set document metadata — custom properties may now be Date or POSIXct — and the workbook-wide formatting defaults, including hyperlink_format = NULL for hyperlinks with no styling at all.

• Page setup and printing — xl_sheet(page = xl_page_setup(...)): orientation, paper size, margins, scaling and fit-to-pages, centring, headers and footers, print area, repeating heading rows and columns, manual page breaks, and the print options.

• Tables — xl_sheet(table = xl_table(...)) and xl_table_column(): a named, styled range with banded rows, a filter dropdown, an optional total row, and per-column headers, formats and formulas.

• Merged cells — xl_sheet(merge = xl_merge(...)). A merged range holds one value, so xl_merge() carries its own; merging over cells the data frame filled keeps only that value, as it does in Excel.

• Images — xl_sheet(image = xl_image(...)), floating over the cells or placed inside one with embed = TRUE. The source may be a file path, a raw vector or an in-memory picture (a raster, colour matrix, RGB array or nativeRaster), so a plot never has to touch the disk. Also a tiled screen backdrop via xl_sheet(background_image =), and images in printed headers and footers. Two arrangements libxlsxwriter miscounts — an embedded image alongside any other, and a header/footer or background image on a sheet before one with a floating image — are refused with the order that works.

• Charts — xl_sheet(chart = xl_chart(...)) and xl_chart_series(), in all 22 types Excel offers, with axes (xl_chart_axis()), the parts of a series (markers, data labels, trendlines, error bars and a format per point) and the chart's own furniture (legend, data table, plot and chart areas, manual layouts). xl_chartsheet() gives one chart a tab of its own.

  A series names its values and categories either as an A1 range ("Data!B2:B10") or by column (list(cols = "revenue")), so a range follows the data when rows are added or a header is written, and a series that plots a column is named after that column's header. Series and titles are styled with the ordinary xl_format() groups — xl_border() becomes the line, xl_fill() the fill, xl_font() the title text — so one format object can style both a cell and a chart.

  Anything the chart cannot draw is refused by name rather than dropped silently, which is what Excel does with it: a format group no chart shape has, a value-axis option on a category axis, a doughnut hole on a bar chart, a data label in a position its chart type disallows. Tests read the function lists out of the bundled chart.h, so a function added upstream surfaces as a failure rather than as a gap.

• A stand-in for missing values via na, which writexl has always written as an empty cell (#76). write_xlsx(df, na = "not measured") sets it for a whole workbook, xl_properties(na = ) does the same on a workbook object, and xl_col_spec(na = ) and xl_cell_general(na = ) narrow it to one column or one cell --- the innermost setting wins. It covers NaN as well as NA, and keeps its own type, so na = 0 writes a number and leaves a numeric column numeric. The default, na = NA, is the empty cell as before.

• Argument names are consistent across the new functions. Whatever a cell, label or box will show is value, whatever its type; a size in pixels says so (width_pixels); and a caption is title, with title_format and title_layout beside it. as.character() methods on xl_cell_general() and xl_rich_string() mean a cell built for a sheet can be reused anywhere a plain string is wanted.

• write_xlsx() now errors informatively when a data frame exceeds the xlsx column limit (16384) or row limit (1048576).

• Bundled libxlsxwriter updated to 1.2.4.

• See the "Getting started with writexl" vignette, and the five that follow it for formatting, worksheets and workbooks, charts and images, formulas and tables, and one runnable example of everything.

Bug fixes

• Fix installation on systems without GNU make, by replacing a GNU-specific pattern rule in src/Makevars with a portable static library recipe (#97).

• Fix a strcpy() buffer overflow in the internal C_set_tempdir(); a tempdir path of 2048 bytes or more now errors informatively.

writexl 1.5.4

• Fix LTO build for bundled libxlsxwriter

writexl 1.5.3

• write_xlsx() now gives a warning if a column is of unsupported type
• Fix crash in write_xlsx() for corrupted data frames

writexl 1.5.2

• Fix parallel make; cleanup after build

writexl 1.5.0

• Update libxlsxwriter from b0c76b33

writexl 1.4.2

• Bugfix for NA timestamps

writexl 1.4.1

• Fix strict-prototypes warnings

writexl 1.4.0

• Update libxlsxwriter to 1.0.3

writexl 1.3.1

• Fix a unit test in R-devel for timezone attribute comparisons

writexl 1.3

• write_xlsx() gains option use_zip64 for 4GB+ file support
• libxlsxwriter error messages are printed to REprintf instead of fprintf
• Handle overly long or duplicate sheet names
• The help assistant only appears once per session

writexl 1.2

• Update bundled libxlsxwriter 0.8.8
• xl_formula() and xl_hyperlink() now correctly support NA
• Oil clippy a bit

writexl 1.1

• Update bundled libxlsxwriter 0.8.4
• Do not write blank xlsx strings for NA and "" character values
• Coerce bit64 vectors to double with warning (xlsx does not have int64)

writexl 1.0

• Save R Date types as proper datetime strings
• Update vendored libxlsxwriter to 0.7.6

writexl 0.2

• Add support for lists in write_xlsx() to create xlsx with multiple sheets
• Automatically coerce columns of type Date and hms to strings

writexl 0.1

• Initial CRAN release with clippy