Merge pull request #3791 from Feoramund/fix-text-table-alignment

Refactor `core:text/table`

core/text/table/doc.odin

@@ -1,18 +1,27 @@
 /*
-The package `table` implements ASCII/markdown/HTML/custom rendering of tables.
+The package `table` implements plain-text/markdown/HTML/custom rendering of tables.
 
 **Custom rendering example:**
 
-	tbl := init(&Table{})
-	padding(tbl, 0, 1)
-	row(tbl, "A_LONG_ENUM", "= 54,", "// A comment about A_LONG_ENUM")
-	row(tbl, "AN_EVEN_LONGER_ENUM", "= 1,", "// A comment about AN_EVEN_LONGER_ENUM")
-	build(tbl)
-	for row in 0..<tbl.nr_rows {
-		for col in 0..<tbl.nr_cols {
-			write_table_cell(stdio_writer(), tbl, row, col)
+	package main
+
+	import "core:io"
+	import "core:text/table"
+
+	main :: proc() {
+		stdout := table.stdio_writer()
+
+		tbl := table.init(&table.Table{})
+		table.padding(tbl, 0, 1)
+		table.row(tbl, "A_LONG_ENUM", "= 54,", "// A comment about A_LONG_ENUM")
+		table.row(tbl, "AN_EVEN_LONGER_ENUM", "= 1,", "// A comment about AN_EVEN_LONGER_ENUM")
+		table.build(tbl, table.unicode_width_proc)
+		for row in 0..<tbl.nr_rows {
+			for col in 0..<tbl.nr_cols {
+				table.write_table_cell(stdout, tbl, row, col)
+			}
+			io.write_byte(stdout, '\n')
 		}
-		io.write_byte(stdio_writer(), '\n')
 	}
 
 This outputs:
@@ -20,47 +29,57 @@ This outputs:
 	A_LONG_ENUM         = 54, // A comment about A_LONG_ENUM
 	AN_EVEN_LONGER_ENUM = 1,  // A comment about AN_EVEN_LONGER_ENUM
 
-**ASCII rendering example:**
+**Plain-text rendering example:**
 
-	tbl := init(&Table{})
-	defer destroy(tbl)
+	package main
 
-	caption(tbl, "This is a table caption and it is very long")
+	import "core:fmt"
+	import "core:io"
+	import "core:text/table"
 
-	padding(tbl, 1, 1) // Left/right padding of cells
+	main :: proc() {
+		stdout := table.stdio_writer()
 
-	header(tbl, "AAAAAAAAA", "B")
-	header(tbl, "C") // Appends to previous header row. Same as if done header("AAAAAAAAA", "B", "C") from start.
+		tbl := table.init(&table.Table{})
+		defer table.destroy(tbl)
 
-	// Create a row with two values. Since there are three columns the third
-	// value will become the empty string.
-	//
-	// NOTE: header() is not allowed anymore after this.
-	row(tbl, 123, "foo")
+		table.caption(tbl, "This is a table caption and it is very long")
 
-	// Use `format()` if you need custom formatting. This will allocate into
-	// the arena specified at init.
-	row(tbl,
-	    format(tbl, "%09d", 5),
-	    format(tbl, "%.6f", 6.28318530717958647692528676655900576))
+		table.padding(tbl, 1, 1) // Left/right padding of cells
 
-	// A row with zero values is allowed as long as a previous row or header
-	// exist. The value and alignment of each cell can then be set
-	// individually.
-	row(tbl)
-		set_cell_value_and_alignment(tbl, last_row(tbl), 0, "a", .Center)
-		set_cell_value(tbl, last_row(tbl), 1, "bbb")
-		set_cell_value(tbl, last_row(tbl), 2, "c")
+		table.header(tbl, "AAAAAAAAA", "B")
+		table.header(tbl, "C") // Appends to previous header row. Same as if done header("AAAAAAAAA", "B", "C") from start.
 
-	// Headers are regular cells, too. Use header_row() as row index to modify
-	// header cells.
-	set_cell_alignment(tbl, header_row(tbl), 1, .Center) // Sets alignment of 'B' column to Center.
-	set_cell_alignment(tbl, header_row(tbl), 2, .Right) // Sets alignment of 'C' column to Right.
+		// Create a row with two values. Since there are three columns the third
+		// value will become the empty string.
+		//
+		// NOTE: table.header() is not allowed anymore after this.
+		table.row(tbl, 123, "foo")
 
-	build(tbl)
+		// Use `format()` if you need custom formatting. This will allocate into
+		// the arena specified at init.
+		table.row(tbl,
+			table.format(tbl, "%09d", 5),
+			table.format(tbl, "%.6f", 6.28318530717958647692528676655900576))
 
-	write_ascii_table(stdio_writer(), tbl)
-	write_markdown_table(stdio_writer(), tbl)
+		// A row with zero values is allowed as long as a previous row or header
+		// exist. The value and alignment of each cell can then be set
+		// individually.
+		table.row(tbl)
+
+		table.set_cell_value_and_alignment(tbl, table.last_row(tbl), 0, "a", .Center)
+		table.set_cell_value(tbl, table.last_row(tbl), 1, "bbb")
+		table.set_cell_value(tbl, table.last_row(tbl), 2, "c")
+
+		// Headers are regular cells, too. Use header_row() as row index to modify
+		// header cells.
+		table.set_cell_alignment(tbl, table.header_row(tbl), 1, .Center) // Sets alignment of 'B' column to Center.
+		table.set_cell_alignment(tbl, table.header_row(tbl), 2, .Right) // Sets alignment of 'C' column to Right.
+
+		table.write_plain_table(stdout, tbl)
+		fmt.println()
+		table.write_markdown_table(stdout, tbl)
+	}
 
 This outputs:
 
@@ -83,5 +102,168 @@ and
 	| a                | bbb             | c        |
 
 respectively.
+
+
+Additionally, if you want to set the alignment and values in-line while
+constructing a table, you can use `aligned_row_of_values` or
+`row_of_aligned_values` like so:
+
+	table.aligned_row_of_values(tbl, .Center, "Foo", "Bar")
+	table.row_of_aligned_values(tbl, {{.Center, "Foo"}, {.Right, "Bar"}})
+
+**Caching Results:**
+
+If you only need to build a table once but display it potentially many times,
+it may be more efficient to cache the results of your write into a string.
+
+Here's an example of how you can do that:
+
+	package main
+
+	import "core:fmt"
+	import "core:strings"
+	import "core:text/table"
+
+	main :: proc() {
+		string_buffer := strings.builder_make()
+		defer strings.builder_destroy(&string_buffer)
+
+		{
+			tbl: table.Table
+			table.init(&tbl)
+			defer table.destroy(&tbl)
+			table.caption(&tbl, "Hellope!")
+			table.row(&tbl, "Hellope", "World")
+
+			builder_writer := strings.to_writer(&string_buffer)
+
+			// The written table will be cached into the string builder after this call.
+			table.write_plain_table(builder_writer, &tbl)
+		}
+		// The table is inaccessible, now that we're back in the first-level scope.
+
+		// But now the results are stored in the string builder, which can be converted to a string.
+		my_table_string := strings.to_string(string_buffer)
+
+		// Remember that the string's allocated backing data lives in the
+		// builder and must still be freed.
+		//
+		// The deferred call to `builder_destroy` will take care of that for us
+		// in this simple example.
+		fmt.println(my_table_string)
+	}
+
+**Regarding `Width_Procs`:**
+
+If you know ahead of time that all the text you're parsing is ASCII, instead of
+Unicode, it is more efficient to use `table.ascii_width_proc` instead of the
+default `unicode_width_proc`, as that procedure has to perform in-depth lookups
+to determine multiple Unicode characteristics of the codepoints parsed in order
+to get the proper alignment for a variety of different scripts.
+
+For example, you may do this instead:
+
+	table.write_plain_table(stdout, tbl, table.ascii_width_proc)
+	table.write_markdown_table(stdout, tbl, table.ascii_width_proc)
+
+The output will still be the same, but the preprocessing is much faster.
+
+
+You may also supply your own `Width_Proc`s, if you know more about how the text
+is structured than what we can assume.
+
+	simple_cjk_width_proc :: proc(str: string) -> (result: int) {
+		for r in str {
+			result += 2
+		}
+		return
+	}
+
+	table.write_plain_table(stdout, tbl, simple_cjk_width_proc)
+
+This procedure will output 2 times the number of UTF-8 runes in a string, a
+simple heuristic for CJK-only wide text.
+
+**Unicode Support:**
+
+This package makes use of the `grapheme_count` procedure from the
+`core:unicode/utf8` package. It is a complete, standards-compliant
+implementation for counting graphemes and calculating visual width of a Unicode
+grapheme cluster in monospace cells.
+
+Here is a full example of how well-supported Unicode is with this package:
+
+	package main
+
+	import "core:fmt"
+	import "core:io"
+	import "core:os"
+	import "core:text/table"
+
+	scripts :: proc(w: io.Writer) {
+		t: table.Table
+		table.init(&t)
+		table.caption(&t, "Tést Suite")
+		table.padding(&t, 1, 3)
+		table.header_of_aligned_values(&t, {{.Left, "Script"}, {.Center, "Sample"}})
+
+		table.row(&t, "Latin", "At vero eos et accusamus et iusto odio dignissimos ducimus,")
+		table.row(&t, "Cyrillic", "Ру́сский язы́к — язык восточнославянской группы славянской")
+		table.row(&t, "Greek", "Η ελληνική γλώσσα ανήκει στην ινδοευρωπαϊκή οικογένεια")
+		table.row(&t, "Younger Futhark", "ᚴᚢᚱᛘᛦ ᚴᚢᚾᚢᚴᛦ ᚴᛅᚱᚦᛁ ᚴᚢᛒᛚ ᚦᚢᛋᛁ ᛅᚠᛏ ᚦᚢᚱᚢᛁ ᚴᚢᚾᚢ ᛋᛁᚾᛅ ᛏᛅᚾᛘᛅᚱᚴᛅᛦ ᛒᚢᛏ")
+		table.row(&t, "Chinese hanzi", "官話為汉语的一支，主體分布在中国北部和西南部的大部分地区。")
+		table.row(&t, "Japanese kana", "いろはにほへとちりぬるをわかよたれそつねならむ")
+		table.row(&t, "Korean hangul", "한글, 조선글은 한국어의 공식문자로서, 세종이 한국어를")
+		table.row(&t, "Thai", "ภาษาไทย หรือ ภาษาไทยกลาง เป็นภาษาในกลุ่มภาษาไท ซึ่งเป็นกลุ่มย่อยของตระกูลภาษาขร้า-ไท")
+		table.row(&t, "Georgian", "ქართული ენა — ქართველურ ენათა ოჯახის ენა. ქართველების მშობლიური ენა,")
+		table.row(&t, "Armenian", "Իր շուրջ հինգհազարամյա գոյության ընթացքում հայերենը շփվել է տարբեր")
+		table.row(&t)
+		table.row_of_aligned_values(&t, {{.Left, "Arabic"}, {.Right, "ٱللُّغَةُ ٱلْعَرَبِيَّة هي أكثر اللغات السامية تحدثًا، وإحدى أكثر"}})
+		table.row_of_aligned_values(&t, {{.Left, "Hebrew"}, {.Right, "עִבְרִית היא שפה שמית, ממשפחת השפות האפרו-אסייתיות, הידועה"}})
+		table.row(&t)
+		table.row(&t, "Swedish", "Växjö [ˈvɛkːˌɧøː] är en tätort i södra Smålands inland samt centralort i Växjö kommun")
+		table.row(&t, "Saxon", "Hwæt! We Gardena in geardagum, þeodcyninga, þrym gefrunon, hu ða æþelingas ellen fremedon.")
+		table.row(&t)
+		table.aligned_row_of_values(&t, .Center, "Emoji (Single codepoints)", "\U0001f4ae \U0001F600 \U0001F201 \U0001F21A")
+		table.row(&t, "Excessive Diacritics", "H̷e̶l̵l̸o̴p̵e̷ ̸w̶o̸r̵l̶d̵!̴")
+
+		table.write_plain_table(w, &t)
+		fmt.println()
+	}
+
+	main :: proc() {
+		stdout := os.stream_from_handle(os.stdout)
+
+		scripts(stdout)
+	}
+
+This will print out:
+
+	+----------------------------------------------------------------------------------------------------------------------------+
+	|                                                        Tést Suite                                                          |
+	+-----------------------------+----------------------------------------------------------------------------------------------+
+	| Script                      |                                           Sample                                             |
+	+-----------------------------+----------------------------------------------------------------------------------------------+
+	| Latin                       | At vero eos et accusamus et iusto odio dignissimos ducimus,                                  |
+	| Cyrillic                    | Ру́сский язы́к — язык восточнославянской группы славянской                                     |
+	| Greek                       | Η ελληνική γλώσσα ανήκει στην ινδοευρωπαϊκή οικογένεια                                       |
+	| Younger Futhark             | ᚴᚢᚱᛘᛦ ᚴᚢᚾᚢᚴᛦ ᚴᛅᚱᚦᛁ ᚴᚢᛒᛚ ᚦᚢᛋᛁ ᛅᚠᛏ ᚦᚢᚱᚢᛁ ᚴᚢᚾᚢ ᛋᛁᚾᛅ ᛏᛅᚾᛘᛅᚱᚴᛅᛦ ᛒᚢᛏ                               |
+	| Chinese hanzi               | 官話為汉语的一支，主體分布在中国北部和西南部的大部分地区。                                   |
+	| Japanese kana               | いろはにほへとちりぬるをわかよたれそつねならむ                                               |
+	| Korean hangul               | 한글, 조선글은 한국어의 공식문자로서, 세종이 한국어를                                        |
+	| Thai                        | ภาษาไทย หรือ ภาษาไทยกลาง เป็นภาษาในกลุ่มภาษาไท ซึ่งเป็นกลุ่มย่อยของตระกูลภาษาขร้า-ไท                     |
+	| Georgian                    | ქართული ენა — ქართველურ ენათა ოჯახის ენა. ქართველების მშობლიური ენა,                         |
+	| Armenian                    | Իր շուրջ հինգհազարամյա գոյության ընթացքում հայերենը շփվել է տարբեր                           |
+	|                             |                                                                                              |
+	| Arabic                      |                                     ٱللُّغَةُ ٱلْعَرَبِيَّة هي أكثر اللغات السامية تحدثًا، وإحدى أكثر   |
+	| Hebrew                      |                                    עִבְרִית היא שפה שמית, ממשפחת השפות האפרו-אסייתיות, הידועה   |
+	|                             |                                                                                              |
+	| Swedish                     | Växjö [ˈvɛkːˌɧøː] är en tätort i södra Smålands inland samt centralort i Växjö kommun        |
+	| Saxon                       | Hwæt! We Gardena in geardagum, þeodcyninga, þrym gefrunon, hu ða æþelingas ellen fremedon.   |
+	|                             |                                                                                              |
+	| Emoji (Single codepoints)   |                                        💮 😀 🈁 🈚                                           |
+	| Excessive Diacritics        | H̷e̶l̵l̸o̴p̵e̷ ̸w̶o̸r̵l̶d̵!̴                                                                               |
+	+-----------------------------+----------------------------------------------------------------------------------------------+
+
 */
 package text_table

core/text/table/table.odin

@@ -4,18 +4,22 @@
 
 	List of contributors:
 		oskarnp: Initial implementation.
+		Feoramund: Unicode support.
 */
 
 package text_table
 
 import "core:io"
 import "core:fmt"
+import "core:log"
 import "core:mem"
 import "core:mem/virtual"
+import "core:unicode/utf8"
 import "base:runtime"
 
 Cell :: struct {
 	text: string,
+	width: int,
 	alignment: Cell_Alignment,
 }
 
@@ -25,6 +29,14 @@ Cell_Alignment :: enum {
 	Right,
 }
 
+Aligned_Value :: struct {
+	alignment: Cell_Alignment,
+	value: any,
+}
+
+// Determines the width of a string used in the table for alignment purposes.
+Width_Proc :: #type proc(str: string) -> int
+
 Table :: struct {
 	lpad, rpad: int, // Cell padding (left/right)
 	cells: [dynamic]Cell,
@@ -34,13 +46,20 @@ Table :: struct {
 	table_allocator: runtime.Allocator,  // Used for allocating cells/colw
 	format_allocator: runtime.Allocator, // Used for allocating Cell.text when applicable
 
-	dirty: bool, // True if build() needs to be called before rendering
-
 	// The following are computed on build()
-	colw: [dynamic]int, // Width of each column (including padding, excluding borders)
+	colw: [dynamic]int, // Width of each column (excluding padding and borders)
 	tblw: int,          // Width of entire table (including padding, excluding borders)
 }
 
+ascii_width_proc :: proc(str: string) -> int {
+	return len(str)
+}
+
+unicode_width_proc :: proc(str: string) -> (width: int) {
+	_, _, width = #force_inline utf8.grapheme_count(str)
+	return
+}
+
 init :: proc{init_with_allocator, init_with_virtual_arena, init_with_mem_arena}
 
 init_with_allocator :: proc(tbl: ^Table, format_allocator := context.temp_allocator, table_allocator := context.allocator) -> ^Table {
@@ -65,13 +84,11 @@ destroy :: proc(tbl: ^Table) {
 
 caption :: proc(tbl: ^Table, value: string) {
 	tbl.caption = value
-	tbl.dirty = true
 }
 
 padding :: proc(tbl: ^Table, lpad, rpad: int) {
 	tbl.lpad = lpad
 	tbl.rpad = rpad
-	tbl.dirty = true
 }
 
 get_cell :: proc(tbl: ^Table, row, col: int, loc := #caller_location) -> ^Cell {
@@ -81,43 +98,47 @@ get_cell :: proc(tbl: ^Table, row, col: int, loc := #caller_location) -> ^Cell {
 	return &tbl.cells[row*tbl.nr_cols + col]
 }
 
-set_cell_value_and_alignment :: proc(tbl: ^Table, row, col: int, value: string, alignment: Cell_Alignment) {
-	cell := get_cell(tbl, row, col)
-	cell.text = format(tbl, "%v", value)
-	cell.alignment = alignment
-	tbl.dirty = true
+@private
+to_string :: #force_inline proc(tbl: ^Table, value: any, loc := #caller_location) -> (result: string) {
+	switch val in value {
+	case nil:
+		result = ""
+	case string:
+		result = val
+	case cstring:
+		result = cast(string)val
+	case:
+		result = format(tbl, "%v", val)
+		if result == "" {
+			log.error("text/table.format() resulted in empty string (arena out of memory?)", location = loc)
+		}
+	}
+	return
 }
 
 set_cell_value :: proc(tbl: ^Table, row, col: int, value: any, loc := #caller_location) {
 	cell := get_cell(tbl, row, col, loc)
-	switch val in value {
-	case nil:
-		cell.text = ""
-	case string:
-		cell.text = string(val)
-	case cstring:
-		cell.text = string(val)
-	case:
-		cell.text = format(tbl, "%v", val)
-		if cell.text == "" {
-			fmt.eprintf("{} text/table: format() resulted in empty string (arena out of memory?)\n", loc)
-		}
-	}
-	tbl.dirty = true
+	cell.text = to_string(tbl, value, loc)
 }
 
 set_cell_alignment :: proc(tbl: ^Table, row, col: int, alignment: Cell_Alignment, loc := #caller_location) {
 	cell := get_cell(tbl, row, col, loc)
 	cell.alignment = alignment
-	tbl.dirty = true
 }
 
-format :: proc(tbl: ^Table, _fmt: string, args: ..any, loc := #caller_location) -> string {
+set_cell_value_and_alignment :: proc(tbl: ^Table, row, col: int, value: any, alignment: Cell_Alignment, loc := #caller_location) {
+	cell := get_cell(tbl, row, col, loc)
+	cell.text = to_string(tbl, value, loc)
+	cell.alignment = alignment
+}
+
+format :: proc(tbl: ^Table, _fmt: string, args: ..any) -> string {
 	context.allocator = tbl.format_allocator
 	return fmt.aprintf(_fmt, ..args)
 }
 
-header :: proc(tbl: ^Table, values: ..any, loc := #caller_location) {
+header :: header_of_values
+header_of_values :: proc(tbl: ^Table, values: ..any, loc := #caller_location) {
 	if (tbl.has_header_row && tbl.nr_rows != 1) || (!tbl.has_header_row && tbl.nr_rows != 0) {
 		panic("Cannot add headers after rows have been added", loc)
 	}
@@ -133,26 +154,108 @@ header :: proc(tbl: ^Table, values: ..any, loc := #caller_location) {
 		set_cell_value(tbl, header_row(tbl), col, val, loc)
 		col += 1
 	}
-
-	tbl.dirty = true
 }
 
-row :: proc(tbl: ^Table, values: ..any, loc := #caller_location) {
+aligned_header_of_values :: proc(tbl: ^Table, alignment: Cell_Alignment, values: ..any, loc := #caller_location) {
+	if (tbl.has_header_row && tbl.nr_rows != 1) || (!tbl.has_header_row && tbl.nr_rows != 0) {
+		panic("Cannot add headers after rows have been added", loc)
+	}
+
+	if tbl.nr_rows == 0 {
+		tbl.nr_rows += 1
+		tbl.has_header_row = true
+	}
+
+	col := tbl.nr_cols
+	tbl.nr_cols += len(values)
+	for val in values {
+		set_cell_value_and_alignment(tbl, header_row(tbl), col, val, alignment, loc)
+		col += 1
+	}
+}
+
+header_of_aligned_values :: proc(tbl: ^Table, aligned_values: []Aligned_Value, loc := #caller_location) {
+	if (tbl.has_header_row && tbl.nr_rows != 1) || (!tbl.has_header_row && tbl.nr_rows != 0) {
+		panic("Cannot add headers after rows have been added", loc)
+	}
+
+	if tbl.nr_rows == 0 {
+		tbl.nr_rows += 1
+		tbl.has_header_row = true
+	}
+
+	col := tbl.nr_cols
+	tbl.nr_cols += len(aligned_values)
+	for av in aligned_values {
+		set_cell_value_and_alignment(tbl, header_row(tbl), col, av.value, av.alignment, loc)
+		col += 1
+	}
+}
+
+row :: row_of_values
+row_of_values :: proc(tbl: ^Table, values: ..any, loc := #caller_location) {
 	if tbl.nr_cols == 0 {
 		if len(values) == 0 {
-			panic("Cannot create row without values unless knowing amount of columns in advance")
+			panic("Cannot create empty row unless the number of columns is known in advance")
 		} else {
 			tbl.nr_cols = len(values)
 		}
 	}
+
 	tbl.nr_rows += 1
+
 	for col in 0..<tbl.nr_cols {
 		val := values[col] if col < len(values) else nil
-		set_cell_value(tbl, last_row(tbl), col, val)
+		set_cell_value(tbl, last_row(tbl), col, val, loc)
 	}
-	tbl.dirty = true
 }
 
+aligned_row_of_values :: proc(tbl: ^Table, alignment: Cell_Alignment, values: ..any, loc := #caller_location) {
+	if tbl.nr_cols == 0 {
+		if len(values) == 0 {
+			panic("Cannot create empty row unless the number of columns is known in advance")
+		} else {
+			tbl.nr_cols = len(values)
+		}
+	}
+
+	tbl.nr_rows += 1
+
+	for col in 0..<tbl.nr_cols {
+		val := values[col] if col < len(values) else nil
+		set_cell_value_and_alignment(tbl, last_row(tbl), col, val, alignment, loc)
+	}
+}
+
+row_of_aligned_values :: proc(tbl: ^Table, aligned_values: []Aligned_Value, loc := #caller_location) {
+	if tbl.nr_cols == 0 {
+		if len(aligned_values) == 0 {
+			panic("Cannot create empty row unless the number of columns is known in advance")
+		} else {
+			tbl.nr_cols = len(aligned_values)
+		}
+	}
+
+	tbl.nr_rows += 1
+
+	for col in 0..<tbl.nr_cols {
+		if col < len(aligned_values) {
+			val := aligned_values[col].value
+			alignment := aligned_values[col].alignment
+			set_cell_value_and_alignment(tbl, last_row(tbl), col, val, alignment, loc)
+		} else {
+			set_cell_value_and_alignment(tbl, last_row(tbl), col, "", .Left, loc)
+		}
+	}
+}
+
+// TODO: This should work correctly when #3262 is fixed.
+// row :: proc {
+// 	row_of_values,
+// 	aligned_row_of_values,
+// 	row_of_aligned_values,
+// }
+
 last_row :: proc(tbl: ^Table) -> int {
 	return tbl.nr_rows - 1
 }
@@ -165,27 +268,24 @@ first_row :: proc(tbl: ^Table) -> int {
 	return header_row(tbl)+1 if tbl.has_header_row else 0
 }
 
-build :: proc(tbl: ^Table) {
-	tbl.dirty = false
-
+build :: proc(tbl: ^Table, width_proc: Width_Proc) {
 	resize(&tbl.colw, tbl.nr_cols)
 	mem.zero_slice(tbl.colw[:])
 
 	for row in 0..<tbl.nr_rows {
 		for col in 0..<tbl.nr_cols {
 			cell := get_cell(tbl, row, col)
-			if w := len(cell.text) + tbl.lpad + tbl.rpad; w > tbl.colw[col] {
-				tbl.colw[col] = w
-			}
+			cell.width = width_proc(cell.text)
+			tbl.colw[col] = max(tbl.colw[col], cell.width)
 		}
 	}
 
 	colw_sum := 0
 	for v in tbl.colw {
-		colw_sum += v
+		colw_sum += v + tbl.lpad + tbl.rpad
 	}
 
-	tbl.tblw = max(colw_sum, len(tbl.caption) + tbl.lpad + tbl.rpad)
+	tbl.tblw = max(colw_sum, width_proc(tbl.caption) + tbl.lpad + tbl.rpad)
 
 	// Resize columns to match total width of table
 	remain := tbl.tblw-colw_sum
@@ -198,13 +298,9 @@ build :: proc(tbl: ^Table) {
 }
 
 write_html_table :: proc(w: io.Writer, tbl: ^Table) {
-	if tbl.dirty {
-		build(tbl)
-	}
-
 	io.write_string(w, "<table>\n")
 	if tbl.caption != "" {
-		io.write_string(w, "<caption>")
+		io.write_string(w, "\t<caption>")
 		io.write_string(w, tbl.caption)
 		io.write_string(w, "</caption>\n")
 	}
@@ -219,45 +315,43 @@ write_html_table :: proc(w: io.Writer, tbl: ^Table) {
 	}
 
 	if tbl.has_header_row {
-		io.write_string(w, "<thead>\n")
-		io.write_string(w, "  <tr>\n")
+		io.write_string(w, "\t<thead>\n")
+		io.write_string(w, "\t\t<tr>\n")
 		for col in 0..<tbl.nr_cols {
 			cell := get_cell(tbl, header_row(tbl), col)
-			io.write_string(w, "    <th")
+			io.write_string(w, "\t\t\t<th")
 			io.write_string(w, align_attribute(cell))
 			io.write_string(w, ">")
 			io.write_string(w, cell.text)
 			io.write_string(w, "</th>\n")
 		}
-		io.write_string(w, "  </tr>\n")
-		io.write_string(w, "</thead>\n")
+		io.write_string(w, "\t\t</tr>\n")
+		io.write_string(w, "\t</thead>\n")
 	}
 
-	io.write_string(w, "<tbody>\n")
+	io.write_string(w, "\t<tbody>\n")
 	for row in 0..<tbl.nr_rows {
 		if tbl.has_header_row && row == header_row(tbl) {
 			continue
 		}
-		io.write_string(w, "  <tr>\n")
+		io.write_string(w, "\t\t<tr>\n")
 		for col in 0..<tbl.nr_cols {
 			cell := get_cell(tbl, row, col)
-			io.write_string(w, "    <td")
+			io.write_string(w, "\t\t\t<td")
 			io.write_string(w, align_attribute(cell))
 			io.write_string(w, ">")
 			io.write_string(w, cell.text)
 			io.write_string(w, "</td>\n")
 		}
-		io.write_string(w, "  </tr>\n")
+		io.write_string(w, "\t\t</tr>\n")
 	}
-	io.write_string(w, "  </tbody>\n")
+	io.write_string(w, "\t</tbody>\n")
 
 	io.write_string(w, "</table>\n")
 }
 
-write_ascii_table :: proc(w: io.Writer, tbl: ^Table) {
-	if tbl.dirty {
-		build(tbl)
-	}
+write_plain_table :: proc(w: io.Writer, tbl: ^Table, width_proc: Width_Proc = unicode_width_proc) {
+	build(tbl, width_proc)
 
 	write_caption_separator :: proc(w: io.Writer, tbl: ^Table) {
 		io.write_byte(w, '+')
@@ -271,7 +365,7 @@ write_ascii_table :: proc(w: io.Writer, tbl: ^Table) {
 			if col == 0 {
 				io.write_byte(w, '+')
 			}
-			write_byte_repeat(w, tbl.colw[col], '-')
+			write_byte_repeat(w, tbl.colw[col] + tbl.lpad + tbl.rpad, '-')
 			io.write_byte(w, '+')
 		}
 		io.write_byte(w, '\n')
@@ -280,8 +374,8 @@ write_ascii_table :: proc(w: io.Writer, tbl: ^Table) {
 	if tbl.caption != "" {
 		write_caption_separator(w, tbl)
 		io.write_byte(w, '|')
-		write_text_align(w, tbl.tblw -  tbl.lpad - tbl.rpad + tbl.nr_cols - 1,
-		                 tbl.lpad, tbl.rpad, tbl.caption, .Center)
+		write_text_align(w, tbl.caption, .Center,
+			tbl.lpad, tbl.rpad, tbl.tblw + tbl.nr_cols - 1 - width_proc(tbl.caption) - tbl.lpad - tbl.rpad)
 		io.write_byte(w, '|')
 		io.write_byte(w, '\n')
 	}
@@ -304,47 +398,56 @@ write_ascii_table :: proc(w: io.Writer, tbl: ^Table) {
 }
 
 // Renders table according to GitHub Flavored Markdown (GFM) specification
-write_markdown_table :: proc(w: io.Writer, tbl: ^Table) {
+write_markdown_table :: proc(w: io.Writer, tbl: ^Table, width_proc: Width_Proc = unicode_width_proc) {
 	// NOTE(oskar): Captions or colspans are not supported by GFM as far as I can tell.
+	build(tbl, width_proc)
 
-	if tbl.dirty {
-		build(tbl)
-	}
-
-	for row in 0..<tbl.nr_rows {
+	write_row :: proc(w: io.Writer, tbl: ^Table, row: int, alignment: Cell_Alignment = .Left) {
 		for col in 0..<tbl.nr_cols {
 			cell := get_cell(tbl, row, col)
 			if col == 0 {
 				io.write_byte(w, '|')
 			}
-			write_text_align(w, tbl.colw[col] - tbl.lpad - tbl.rpad, tbl.lpad, tbl.rpad, cell.text,
-			                 .Center if tbl.has_header_row && row == header_row(tbl) else .Left)
+			write_text_align(w, cell.text, alignment, tbl.lpad, tbl.rpad, tbl.colw[col] - cell.width)
 			io.write_string(w, "|")
 		}
 		io.write_byte(w, '\n')
+	}
 
-		if tbl.has_header_row && row == header_row(tbl) {
-			for col in 0..<tbl.nr_cols {
-				cell := get_cell(tbl, row, col)
-				if col == 0 {
-					io.write_byte(w, '|')
-				}
-				switch cell.alignment {
-				case .Left:
-					io.write_byte(w, ':')
-					write_byte_repeat(w, max(1, tbl.colw[col]-1), '-')
-				case .Center:
-					io.write_byte(w, ':')
-					write_byte_repeat(w, max(1, tbl.colw[col]-2), '-')
-					io.write_byte(w, ':')
-				case .Right:
-					write_byte_repeat(w, max(1, tbl.colw[col]-1), '-')
-					io.write_byte(w, ':')
-				}
+	start := 0
+
+	if tbl.has_header_row {
+		row := header_row(tbl)
+
+		write_row(w, tbl, row, .Center)
+
+		for col in 0..<tbl.nr_cols {
+			cell := get_cell(tbl, row, col)
+			if col == 0 {
 				io.write_byte(w, '|')
 			}
-			io.write_byte(w, '\n')
+			divider_width := tbl.colw[col] + tbl.lpad + tbl.rpad - 1
+			switch cell.alignment {
+			case .Left:
+				io.write_byte(w, ':')
+				write_byte_repeat(w, max(1, divider_width), '-')
+			case .Center:
+				io.write_byte(w, ':')
+				write_byte_repeat(w, max(1, divider_width - 1), '-')
+				io.write_byte(w, ':')
+			case .Right:
+				write_byte_repeat(w, max(1, divider_width), '-')
+				io.write_byte(w, ':')
+			}
+			io.write_byte(w, '|')
 		}
+		io.write_byte(w, '\n')
+
+		start += row + 1
+	}
+
+	for row in start..<tbl.nr_rows {
+		write_row(w, tbl, row)
 	}
 }
 
@@ -355,27 +458,22 @@ write_byte_repeat :: proc(w: io.Writer, n: int, b: byte) {
 }
 
 write_table_cell :: proc(w: io.Writer, tbl: ^Table, row, col: int) {
-	if tbl.dirty {
-		build(tbl)
-	}
 	cell := get_cell(tbl, row, col)
-	write_text_align(w, tbl.colw[col]-tbl.lpad-tbl.rpad, tbl.lpad, tbl.rpad, cell.text, cell.alignment)
+	write_text_align(w, cell.text, cell.alignment, tbl.lpad, tbl.rpad, tbl.colw[col] - cell.width)
 }
 
-write_text_align :: proc(w: io.Writer, colw, lpad, rpad: int, text: string, alignment: Cell_Alignment) {
+write_text_align :: proc(w: io.Writer, text: string, alignment: Cell_Alignment, lpad, rpad, space: int) {
 	write_byte_repeat(w, lpad, ' ')
 	switch alignment {
 	case .Left:
 		io.write_string(w, text)
-		write_byte_repeat(w, colw - len(text), ' ')
+		write_byte_repeat(w, space, ' ')
 	case .Center:
-		pad := colw - len(text)
-		odd := pad & 1 != 0
-		write_byte_repeat(w, pad/2, ' ')
+		write_byte_repeat(w, space/2, ' ')
 		io.write_string(w, text)
-		write_byte_repeat(w, pad/2 + 1 if odd else pad/2, ' ')
+		write_byte_repeat(w, space/2 + space & 1, ' ')
 	case .Right:
-		write_byte_repeat(w, colw - len(text), ' ')
+		write_byte_repeat(w, space, ' ')
 		io.write_string(w, text)
 	}
 	write_byte_repeat(w, rpad, ' ')