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diff --git a/lib/lyaml/explicit.lua b/lib/lyaml/explicit.lua
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+-- LYAML parse explicit token values.
+-- Written by Gary V. Vaughan, 2015
+--
+-- Copyright(C) 2015-2022 Gary V. Vaughan
+--
+-- Permission is hereby granted, free of charge, to any person obtaining
+-- a copy of this software and associated documentation files(the
+-- "Software"), to deal in the Software without restriction, including
+-- without limitation the rights to use, copy, modify, merge, publish,
+-- distribute, sublicense, and/or sell copies of the Software, and to
+-- permit persons to whom the Software is furnished to do so, subject to
+-- the following conditions:
+--
+-- The above copyright notice and this permission notice shall be
+-- included in all copies or substantial portions of the Software.
+--
+-- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+-- EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+-- MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+-- IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+-- CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+-- TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+-- SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+--- @module lyaml.explicit
+
+local functional = require 'lyaml.functional'
+local implicit = require 'lyaml.implicit'
+
+local NULL = functional.NULL
+local anyof = functional.anyof
+local id = functional.id
+
+
+local yn = {y=true, Y=true, n=false, N=false}
+
+
+--- Parse the value following an explicit `!!bool` tag.
+-- @function bool
+-- @param value token
+-- @treturn[1] bool boolean equivalent, if a valid value was recognized
+-- @treturn[2] nil otherwise, nil
+-- @usage maybe_bool = explicit.bool(tagarg)
+local bool = anyof {
+   implicit.bool,
+   function(x) return yn[x] end,
+}
+
+
+--- Return a function that converts integer results to equivalent float.
+-- @tparam function fn token parsing function
+-- @treturn function new function that converts int results to float
+-- @usage maybe_float = maybefloat(implicit.decimal)(tagarg)
+local function maybefloat(fn)
+   return function(...)
+      local r = fn(...)
+      if type(r) == 'number' then
+         return r + 0.0
+      end
+   end
+end
+
+
+--- Parse the value following an explicit `!!float` tag.
+-- @function float
+-- @param value token
+-- @treturn[1] number float equivalent, if a valid value was recognized
+-- @treturn[2] nil otherwise, nil
+-- @usage maybe_float = explicit.float(tagarg)
+local float = anyof {
+   implicit.float,
+   implicit.nan,
+   implicit.inf,
+   maybefloat(implicit.octal),
+   maybefloat(implicit.decimal),
+   maybefloat(implicit.hexadecimal),
+   maybefloat(implicit.binary),
+   implicit.sexfloat,
+}
+
+
+--- Parse the value following an explicit `!!int` tag.
+-- @function int
+-- @param value token
+-- @treturn[1] int integer equivalent, if a valid value was recognized
+-- @treturn[2] nil otherwise, nil
+-- @usage maybe_int = explicit.int(tagarg)
+local int = anyof {
+   implicit.octal,
+   implicit.decimal,
+   implicit.hexadecimal,
+   implicit.binary,
+   implicit.sexagesimal,
+}
+
+
+--- Parse an explicit `!!null` tag.
+-- @treturn lyaml.null
+-- @usage null = explicit.null(tagarg)
+local function null()
+   return NULL
+end
+
+
+--- Parse the value following an explicit `!!str` tag.
+-- @function str
+-- @tparam string value token
+-- @treturn string *value* which was a string already
+-- @usage tagarg = explicit.str(tagarg)
+local str = id
+
+
+--- @export
+return {
+   bool = bool,
+   float = float,
+   int = int,
+   null = null,
+   str = str,
+}