feat: decimal fraction

doc/dial.jax

@@ -20,6 +20,7 @@ Configurations					|dial-config|
   Augends						|dial-augends|
     Number						|dial-augends-number|
     Date						|dial-augends-date|
+    Decimal Fraction			|dial-augends-decimal-fraction|
     Constant					|dial-augends-constant|
     Case						|dial-augends-case|
     Hexcolor					|dial-augends-hexcolor|
@@ -868,6 +869,90 @@ augend.date.alias["%H:%M"]~
 がインクリメントされます。
 意図しないマッチを避けるため、存在しない時刻にはマッチしません。
 
+DECIMAL FRACTION						*dial-augends-decimal-fraction*
+----------------
+
+小数を増減します。
+`augend.decimal_fraction.new{ ...opts }` で使用できます。
+>
+	require("dial.config").augends:register_group{
+	  default = {
+		augend.decimal_fraction.new{
+			signed = false,
+			point_char = ".",
+		},
+	  },
+	}
+<
+
+以下のパラメータを有します。
+		signed (boolean, default: false)
+				true のとき、小数に前置されたマイナスを加味します。
+		point_char (string, default: `.`)
+				小数点を表す文字。1文字である必要があります。基本的には `.` か
+				`,` のどちらかです。
+
+decimal_fraction は `42.195` や `9.80665` といった小数を見つけたとき、カーソル
+が整数部分の前にあれば整数部分を、小数部分の前にあれば小数部分を増減します。
+
+たとえば
+>
+	42.195
+<
+という文字列の `4` にカーソルがある状態で |<Plug>(dial-increment)| を行うと
+>
+	43.195
+<
+となり、さらに`1` にカーソルがある状態で |<Plug>(dial-increment)| を行うと
+>
+	43.196
+<
+となります。カウンタを指定することもでき、小数部分にカーソルを当てて
+|100<Plug>(dial-increment)| を実行すれば
+>
+	43.296
+<
+となります。
+
+上記の挙動だけ見ると integer を指定したときの挙動とほとんど変わらないと感じら
+れるかも知れません。しかし、integer とは以下の2つの違いがあります。
+
+* 繰り上がりや繰り下がりが発生します。すなわち
+>
+	2.9
+<
+の小数部分にカーソルを当てて |<Plug>(dial-increment)| を行うと、
+>
+	3.0
+<
+となります（integer を指定したときは `2.10` となっていました）。
+これは減算でも同様です。 `signed = true` の設定で
+>
+	0.7
+<
+の整数部分にカーソルを当てて |<Plug>(dial-decrement)| を行うと、
+>
+	-0.3
+<
+となります (`0.7 - 1 = -0.3`)。
+
+* ドットリピートは「増減する実際の値」を記憶し、再現します。`2.8` の小数部分を
+  インクリメントして `2.9` にした直後なら、 `1.73` をドットリピートでインクリ
+  メントしたときの結果は `1.74` ではなく `1.83` となります。
+
+`augend.decimal_fraction` と `augend.integer` を両立することもできます。
+>
+	require("dial.config").augends:register_group{
+	  default = {
+		augend.integer.alias.decimal,
+		augend.decimal_fraction.new{ },
+	  },
+	}
+<
+
+この場合はカーソル下または直後にある数字が小数であるときに限り、
+decimal_fraction による増減ルールが適用されます。
+
 CONSTANT								*dial-augends-constant*
 --------
 

doc/dial.txt

@@ -21,6 +21,7 @@ Configurations					|dial-config|
   Augends						|dial-augends|
     Number						|dial-augends-number|
     Date						|dial-augends-date|
+    Decimal Fraction			|dial-augends-decimal-fraction|
     Constant					|dial-augends-constant|
     Case						|dial-augends-case|
     Hexcolor					|dial-augends-hexcolor|
@@ -904,6 +905,87 @@ target of the increment.
 The format matches times that do not exist in reality such as `52:99`, and
 the time is corrected to a date that actually exists when incrementing.
 
+DECIMAL FRACTION						*dial-augends-decimal-fraction*
+----------------
+
+Represents decimal fraction number, such as `42.195` and `-9.80665`.
+`augend.decimal_fraction.new{ ...opts }` で使用できます。
+>
+	require("dial.config").augends:register_group{
+	  default = {
+		augend.decimal_fraction.new{
+			signed = false,
+			point_char = ".",
+		},
+	  },
+	}
+<
+
+The argument table of `augend.decimal_fraction.new` can take the following
+keys:
+		signed (boolean, default: false)
+			If true, add the minus prefixed to the decimal.
+		point_char (string, default: `.`)
+			A decimal point character, which must be a single character.
+			Either "." or "," in most cases.
+
+When decimal_fraction augend finds a fraction such as `42.195` or `9.80665`,
+it increments/decrements:
+* the integer part if the cursor is on/before the integer part,
+* the fractional part if the cursor is on/before the fractional part.
+
+For instance, if you perform |<Plug>(dial-increment)| with the cursor at `4`
+of the following string:
+>
+	42.195
+<
+then you will get the following result.
+>
+	43.195
+<
+And if you perform |<Plug>(dial-increment)| with the cursor at `1` in
+succession, you will get the following result.
+>
+	43.196
+<
+You can specify the [count]. By performing |100<Plug>(dial-increment)| on the
+fractional part, you will get:
+>
+	43.296
+<
+
+You may feel that the behavior is almost the same as when an integer is
+specified. However, there are two important differences from integer:
+
+* the value is carried across the decimal point. e.g., if you perform
+  |<Plug>(dial-increment)| on the fractional part of the following:
+>
+	2.9
+<
+you will get:
+>
+	3.0
+<
+If you had specified `integer` augend, you would have got `2.10`.
+
+* Dot repeat remembers and reproduces the "actual value to be increased or
+  decreased." Immediately after incrementing the decimal portion of `2.8`
+  to `2.9,` the result of dot repeat incrementing `1.73` would be `1.83`,
+  not `1.74`.
+
+You can also use both `augend.decimal_fraction` and `augend.integer`:
+>
+	require("dial.config").augends:register_group{
+	  default = {
+		augend.integer.alias.decimal,
+		augend.decimal_fraction.new{ },
+	  },
+	}
+<
+
+In this case, the increment/decrement rule by `decimal_fraction` is applied
+only when the number after/on the cursor is a decimal fraction number.
+
 CONSTANT								*dial-augends-constant*
 --------
 

lua/dial/augend.lua

@@ -1,6 +1,7 @@
 local case = require "dial.augend.case"
 local constant = require "dial.augend.constant"
 local date = require "dial.augend.date"
+local decimal_fraction = require "dial.augend.decimal_fraction"
 local hexcolor = require "dial.augend.hexcolor"
 local integer = require "dial.augend.integer"
 local semver = require "dial.augend.semver"
@@ -12,6 +13,7 @@ return {
     case = case,
     constant = constant,
     date = date,
+    decimal_fraction = decimal_fraction,
     hexcolor = hexcolor,
     integer = integer,
     semver = semver,

lua/dial/augend/decimal_fraction.lua

@@ -0,0 +1,150 @@
+local common = require "dial.augend.common"
+local util = require "dial.util"
+
+---@class AugendDecimalFraction
+---@implement Augend
+---@field signed boolean
+---@field point_char string
+local AugendDecimalFraction = {}
+
+local M = {}
+
+---@param config { signed?: boolean, point_char?: string }
+---@return Augend
+function M.new(config)
+    vim.validate {
+        signed = { config.signed, "boolean", true },
+        point_char = { config.point_char, "string", true },
+    }
+
+    local signed = util.unwrap_or(config.signed, false)
+    local point_char = util.unwrap_or(config.point_char, ".")
+    local digits_to_add = 0
+
+    return setmetatable({
+        signed = signed,
+        point_char = point_char,
+        digits_to_add = digits_to_add,
+    }, { __index = AugendDecimalFraction })
+end
+
+---@param line string
+---@param cursor? integer
+---@return textrange?
+function AugendDecimalFraction:find(line, cursor)
+    local idx = 1
+    local integer_pattern
+    if self.signed then
+        integer_pattern = "%-?%d+"
+    else
+        integer_pattern = "%d+"
+    end
+    while idx <= #line do
+        local idx_integer_start, idx_integer_end = line:find(integer_pattern, idx)
+        if idx_integer_start == nil then
+            break
+        end
+
+        local result = (function()
+            idx = idx_integer_end + 1
+            -- invalid decimal fraction format
+            if line:sub(idx, idx) ~= self.point_char then
+                return -- continue while loop
+            end
+            idx = idx + 1
+            local idx_frac_start, idx_frac_end = line:find("^%d+", idx)
+            -- invalid decimal fraction format
+            if idx_frac_start == nil then
+                return -- continue while loop
+            end
+            idx = idx_frac_end + 1
+            -- decimal fraction before the cursor
+            if idx_frac_end < cursor then
+                return -- continue while loop
+            end
+
+            -- negative lookahead
+            if line:sub(idx, idx) == self.point_char then
+                return -- continue while loop
+            end
+            -- break loop and return value
+            return { from = idx_integer_start, to = idx_frac_end }
+        end)()
+
+        if result ~= nil then
+            return result
+        end
+    end
+end
+
+---@param line string
+---@param cursor? integer
+---@return textrange?
+function AugendDecimalFraction:find_stateful(line, cursor)
+    local result = self:find(line, cursor)
+    if result == nil then
+        return nil
+    end
+
+    local point_pos = line:find(self.point_char, result.from, true)
+    if cursor < point_pos then
+        -- increment integer part
+        self.digits_to_add = 0
+    else
+        -- increment decimal part
+        self.digits_to_add = result.to - point_pos
+    end
+    return result
+end
+
+---@param text string
+---@param addend integer
+---@param cursor? integer
+---@return { text?: string, cursor?: integer }
+function AugendDecimalFraction:add(text, addend, cursor)
+    local point_pos = text:find(self.point_char, 1, true)
+
+    local int_part = text:sub(1, point_pos - 1)
+    local frac_part = text:sub(point_pos + 1)
+
+    -- 桁数調整。元の数字が 12.3 なのに 0.01 を足したいとき、 12.31 になるようにする
+    if #frac_part < self.digits_to_add then
+        frac_part = frac_part .. ("0"):rep(self.digits_to_add - #frac_part)
+    end
+
+    local num = tonumber(int_part .. frac_part)
+    local add_num = addend * math.floor(10 ^ (#frac_part - self.digits_to_add))
+    num = num + add_num
+    if not self.signed and num < 0 then
+        num = 0
+    end
+    local str_num = tostring(num)
+
+    if num < 0 then
+        if #str_num - 1 <= #frac_part then
+            str_num = "-" .. ("0"):rep(#frac_part + 2 - #str_num) .. str_num:sub(2)
+        end
+    else
+        if #str_num <= #frac_part then
+            str_num = ("0"):rep(#frac_part + 1 - #str_num) .. str_num
+        end
+    end
+
+    -- pad as necessary
+    local new_int_part = str_num:sub(1, #str_num - #frac_part)
+    local new_dec_part = str_num:sub(#str_num - #frac_part + 1)
+
+    text = new_int_part .. "." .. new_dec_part
+    if self.digits_to_add == 0 then
+        -- incremented integer part
+        cursor = #new_int_part
+    else
+        cursor = #text
+    end
+
+    return { text = text, cursor = cursor }
+end
+
+M.alias = {}
+
+return M