From 976aa4fbee8a070f362cab6f6ec84e9251a90cf9 Mon Sep 17 00:00:00 2001
From: William Boman <william@redwill.se>
Date: Fri, 8 Jul 2022 18:34:38 +0200
Subject: refactor: add mason-schemas and mason-core modules (#29)

* refactor: add mason-schemas and move generated filetype map to mason-lspconfig

* refactor: add mason-core module
---
 lua/mason-core/optional.lua | 100 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 100 insertions(+)
 create mode 100644 lua/mason-core/optional.lua

(limited to 'lua/mason-core/optional.lua')

diff --git a/lua/mason-core/optional.lua b/lua/mason-core/optional.lua
new file mode 100644
index 00000000..10af8ccb
--- /dev/null
+++ b/lua/mason-core/optional.lua
@@ -0,0 +1,100 @@
+---@class Optional<T>
+---@field private _value unknown
+local Optional = {}
+Optional.__index = Optional
+
+---@param value any
+function Optional.new(value)
+    return setmetatable({ _value = value }, Optional)
+end
+
+local EMPTY = Optional.new(nil)
+
+---@param value any
+function Optional.of_nilable(value)
+    if value == nil then
+        return EMPTY
+    else
+        return Optional.new(value)
+    end
+end
+
+function Optional.empty()
+    return EMPTY
+end
+
+---@param value any
+function Optional.of(value)
+    return Optional.new(value)
+end
+
+---@param mapper_fn fun(value: any): any
+function Optional:map(mapper_fn)
+    if self:is_present() then
+        return Optional.of_nilable(mapper_fn(self._value))
+    else
+        return EMPTY
+    end
+end
+
+function Optional:get()
+    if not self:is_present() then
+        error("No value present.", 2)
+    end
+    return self._value
+end
+
+---@param value any
+function Optional:or_else(value)
+    if self:is_present() then
+        return self._value
+    else
+        return value
+    end
+end
+
+---@param supplier fun(): any
+function Optional:or_else_get(supplier)
+    if self:is_present() then
+        return self._value
+    else
+        return supplier()
+    end
+end
+
+---@param supplier fun(): Optional
+---@return Optional
+function Optional:or_(supplier)
+    if self:is_present() then
+        return self
+    else
+        return supplier()
+    end
+end
+
+---@param exception any @(optional) The exception to throw if the result is a failure.
+function Optional:or_else_throw(exception)
+    if self:is_present() then
+        return self._value
+    else
+        if exception then
+            error(exception, 2)
+        else
+            error("No value present.", 2)
+        end
+    end
+end
+
+---@param fn fun(value: any)
+function Optional:if_present(fn)
+    if self:is_present() then
+        fn(self._value)
+    end
+    return self
+end
+
+function Optional:is_present()
+    return self._value ~= nil
+end
+
+return Optional
-- 
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