added default values

README.md

@@ -34,15 +34,14 @@ TODO L1
 =======
 
 * More tests
-* Add defaults
+* Add converters
 * Improve error messages: delegate them to parser, have separate methods for each error type
 
 TODO L2
 =======
 
-* Add converters
 * Add choices
-* Make interface decalrative
+* Make interface declarative
 * Refactor Parser
 * Write primitive ugly usage and help message generation
 

spec/default_spec.lua

@@ -0,0 +1,84 @@
+local largparse = require "largparse"
+
+describe("tests related to default values", function()
+   describe("default values for arguments", function()
+      it("handles default argument correctly", function()
+         local parser = largparse.parser()
+         parser:argument("foo", {
+            default = "bar"
+         })
+         local args = parser:parse({})
+         assert.same(args, {foo = "bar"})
+      end)
+
+      it("handles default multi-argument correctly", function()
+         local parser = largparse.parser()
+         parser:argument("foo", {
+            args = 3,
+            default = "bar"
+         })
+         local args = parser:parse({"baz"})
+         assert.same(args, {foo = {"baz", "bar", "bar"}})
+      end)
+
+      it("does not use default values if not needed", function()
+         local parser = largparse.parser()
+         parser:argument("foo", {
+            args = "1-2",
+            default = "bar"
+         })
+         local args = parser:parse({"baz"})
+         assert.same(args, {foo = {"baz"}})
+      end)
+   end)
+
+   describe("default values for options", function()
+      it("handles option with default value correctly", function()
+         local parser = largparse.parser()
+         parser:option("-f", "--foo", {
+            default = "bar"
+         })
+         local args = parser:parse({"-f"})
+         assert.same(args, {foo = "bar"})
+      end)
+
+      it("doesn't use default if option is not invoked", function()
+         local parser = largparse.parser()
+         parser:option("-f", "--foo", {
+            default = "bar"
+         })
+         local args = parser:parse({})
+         assert.same(args, {})
+      end)
+
+      it("handles default multi-argument correctly", function()
+         local parser = largparse.parser()
+         parser:option("-f", "--foo", {
+            args = 3,
+            default = "bar"
+         })
+         local args = parser:parse({"--foo=baz"})
+         assert.same(args, {foo = {"baz", "bar", "bar"}})
+      end)
+
+      it("does not use default values if not needed", function()
+         local parser = largparse.parser()
+          parser:option("-f", "--foo", {
+            args = "1-2",
+            default = "bar"
+         })
+         local args = parser:parse({"-f", "baz"})
+         assert.same(args, {foo = {"baz"}})
+      end)
+
+      it("handles multi-count options with default value correctly", function()
+         local parser = largparse.parser()
+          parser:option("-f", "--foo", {
+            count = "*",
+            default = "bar"
+         })
+         local args = parser:parse({"-f", "--foo=baz", "--foo"})
+         assert.same(args, {foo = {"bar", "baz", "bar"}})
+      end)
+   end)
+end)

src/state.lua

@@ -112,7 +112,15 @@ function State:_check()
 
       for _, passed in ipairs(invocations) do
          self:_assert(#passed <= element.maxargs, "too many arguments")
-         self:_assert(#passed >= element.minargs, "too few arguments")
+         if #passed < element.minargs then
+            if element.default then
+               for i = 1, element.minargs-#passed do
+                  table.insert(passed, element.default)
+               end 
+            else
+               self:_error("too few arguments")
+            end
+         end
       end
 
       self._result[element.target] = invocations