refactor: taskfile/ast package (#1450)

* refactor: ast package

* feat: read -> taskfile

* refactor: taskfile.Taskfile -> taskfile.Read

* refactor: move merge function back into taskfile package

* refactor: rename taskfile.go to read.go

taskfile/ast/taskfile_test.go

@@ -0,0 +1,98 @@
+package ast_test
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"gopkg.in/yaml.v3"
+
+	"github.com/go-task/task/v3/internal/orderedmap"
+	"github.com/go-task/task/v3/taskfile/ast"
+)
+
+func TestCmdParse(t *testing.T) {
+	const (
+		yamlCmd      = `echo "a string command"`
+		yamlDep      = `"task-name"`
+		yamlTaskCall = `
+task: another-task
+vars:
+  PARAM1: VALUE1
+  PARAM2: VALUE2
+`
+		yamlDeferredCall = `defer: { task: some_task, vars: { PARAM1: "var" } }`
+		yamlDeferredCmd  = `defer: echo 'test'`
+	)
+	tests := []struct {
+		content  string
+		v        any
+		expected any
+	}{
+		{
+			yamlCmd,
+			&ast.Cmd{},
+			&ast.Cmd{Cmd: `echo "a string command"`},
+		},
+		{
+			yamlTaskCall,
+			&ast.Cmd{},
+			&ast.Cmd{
+				Task: "another-task", Vars: &ast.Vars{
+					OrderedMap: orderedmap.FromMapWithOrder(
+						map[string]ast.Var{
+							"PARAM1": {Value: "VALUE1"},
+							"PARAM2": {Value: "VALUE2"},
+						},
+						[]string{"PARAM1", "PARAM2"},
+					),
+				},
+			},
+		},
+		{
+			yamlDeferredCmd,
+			&ast.Cmd{},
+			&ast.Cmd{Cmd: "echo 'test'", Defer: true},
+		},
+		{
+			yamlDeferredCall,
+			&ast.Cmd{},
+			&ast.Cmd{
+				Task: "some_task", Vars: &ast.Vars{
+					OrderedMap: orderedmap.FromMapWithOrder(
+						map[string]ast.Var{
+							"PARAM1": {Value: "var"},
+						},
+						[]string{"PARAM1"},
+					),
+				},
+				Defer: true,
+			},
+		},
+		{
+			yamlDep,
+			&ast.Dep{},
+			&ast.Dep{Task: "task-name"},
+		},
+		{
+			yamlTaskCall,
+			&ast.Dep{},
+			&ast.Dep{
+				Task: "another-task", Vars: &ast.Vars{
+					OrderedMap: orderedmap.FromMapWithOrder(
+						map[string]ast.Var{
+							"PARAM1": {Value: "VALUE1"},
+							"PARAM2": {Value: "VALUE2"},
+						},
+						[]string{"PARAM1", "PARAM2"},
+					),
+				},
+			},
+		},
+	}
+	for _, test := range tests {
+		err := yaml.Unmarshal([]byte(test.content), test.v)
+		require.NoError(t, err)
+		assert.Equal(t, test.expected, test.v)
+	}
+}