feat(functional): add split_every and default_to (#835)

5 files changed, 50 insertions, 0 deletions

diff --git a/lua/mason-core/functional/init.lua b/lua/mason-core/functional/init.lua
index 153c40aa..9b52047c 100644
--- a/lua/mason-core/functional/init.lua
+++ b/lua/mason-core/functional/init.lua
@@ -62,6 +62,7 @@ _.take = list.take
 _.drop = list.drop
 _.drop_last = list.drop_last
 _.reduce = list.reduce
+_.split_every = list.split_every
 
 ---@module "mason-core.functional.relation"
 local relation = lazy_require "mason-core.functional.relation"
@@ -80,6 +81,7 @@ _.if_else = logic.if_else
 _.is_not = logic.is_not
 _.complement = logic.complement
 _.cond = logic.cond
+_.default_to = logic.default_to
 
 ---@module "mason-core.functional.number"
 local number = lazy_require "mason-core.functional.number"
diff --git a/lua/mason-core/functional/list.lua b/lua/mason-core/functional/list.lua
index 8c216c4d..275bc61a 100644
--- a/lua/mason-core/functional/list.lua
+++ b/lua/mason-core/functional/list.lua
@@ -269,4 +269,19 @@ _.reduce = fun.curryN(function(fn, acc, list)
     return acc
 end, 3)
 
+---@generic T
+---@param n integer
+---@param list T[]
+---@return T[][]
+_.split_every = fun.curryN(function(n, list)
+    assert(n > 0, "n needs to be greater than 0.")
+    local res = {}
+    local idx = 1
+    while idx <= #list do
+        table.insert(res, { unpack(list, idx, idx + n - 1) })
+        idx = idx + n
+    end
+    return res
+end, 2)
+
 return _
diff --git a/lua/mason-core/functional/logic.lua b/lua/mason-core/functional/logic.lua
index 125a94ee..79e02361 100644
--- a/lua/mason-core/functional/logic.lua
+++ b/lua/mason-core/functional/logic.lua
@@ -69,4 +69,16 @@ _.cond = fun.curryN(function(predicate_transformer_pairs, value)
     end
 end, 2)
 
+---@generic T
+---@param default_val T
+---@param val T?
+---@return T
+_.default_to = fun.curryN(function(default_val, val)
+    if val ~= nil then
+        return val
+    else
+        return default_val
+    end
+end, 2)
+
 return _
diff --git a/tests/mason-core/functional/list_spec.lua b/tests/mason-core/functional/list_spec.lua
index 6c14e5a9..043f058b 100644
--- a/tests/mason-core/functional/list_spec.lua
+++ b/tests/mason-core/functional/list_spec.lua
@@ -264,6 +264,21 @@ describe("functional: list", function()
         assert.spy(add).was_called_with(6, 4)
         assert.spy(add).was_called_with(10, 5)
     end)
+
+    it("should split lists", function()
+        assert.same({
+            { 1, 2, 3 },
+            { 4, 5, 6 },
+            { 7 },
+        }, _.split_every(3, { 1, 2, 3, 4, 5, 6, 7 }))
+
+        assert.same({ { 1, 2, 3 } }, _.split_every(5, { 1, 2, 3 }))
+        assert.same({ { 1 }, { 2 }, { 3 } }, _.split_every(1, { 1, 2, 3 }))
+
+        assert.has_error(function()
+            _.split_every(0, {})
+        end)
+    end)
 end)
 
 describe("list immutability", function()
diff --git a/tests/mason-core/functional/logic_spec.lua b/tests/mason-core/functional/logic_spec.lua
index 7c795443..b15fd6ae 100644
--- a/tests/mason-core/functional/logic_spec.lua
+++ b/tests/mason-core/functional/logic_spec.lua
@@ -54,4 +54,10 @@ describe("functional: logic", function()
         assert.is_true(_.complement(_.is_nil, "not nil"))
         assert.is_false(_.complement(_.is_nil, nil))
     end)
+
+    it("should default to provided value", function()
+        local fortytwo = _.default_to(42)
+        assert.equals(42, fortytwo(nil))
+        assert.equals(1337, fortytwo(1337))
+    end)
 end)