Merge pull request #145 from Flipez/add-raise

[object/error] Add `raise()` builtin

docs/docs/literals/error.md

@@ -6,6 +6,8 @@ The documentation of those functions does indicate ERROR as a potential return v
 
 A program can rescue from errors within a block or alter it's behavior within other blocks like 'if' or 'def'.
 
+It is possible for the user to create errors using 'raise(STRING)' which will return an ERROR object with STRING as the message.
+
 
 
 ```js
@@ -50,7 +52,7 @@ Please note that performing `.msg()` on a ERROR object does result in a STRING o
 
 
 ```js
-» def ()
+» def test()
 puts(nope)
 rescue e
 puts((rescued error: + e.msg()))

docs/generate.go

@@ -155,6 +155,8 @@ An error does often replace the original return value of a function or identifie
 The documentation of those functions does indicate ERROR as a potential return value.
 
 A program can rescue from errors within a block or alter it's behavior within other blocks like 'if' or 'def'.
+
+It is possible for the user to create errors using 'raise(STRING)' which will return an ERROR object with STRING as the message.
 `,
 		Example: `def test()
   puts(nope)

evaluator/evaluator_test.go

@@ -221,6 +221,7 @@ func TestErrorHandling(t *testing.T) {
 		{"begin puts(nope) end", "identifier not found: nope"},
 		{"begin puts(nope) rescue e e.nope() end", "undefined method `.nope()` for ERROR"},
 		{"a = begin puts(nope) rescue e e.msg() end; a.nope()", "undefined method `.nope()` for STRING"},
+		{`raise("custom error")`, "custom error"},
 	}
 
 	for _, tt := range tests {

stdlib/raise.go

@@ -0,0 +1,9 @@
+package stdlib
+
+import (
+	"github.com/flipez/rocket-lang/object"
+)
+
+func raiseFunction(_ object.Environment, args ...object.Object) object.Object {
+	return object.NewError(args[0].(*object.String).Value)
+}

stdlib/std.go

@@ -9,6 +9,14 @@ var Modules = map[string]*object.BuiltinModule{}
 
 func init() {
 	RegisterFunction("puts", object.MethodLayout{ArgPattern: object.Args(object.Arg(object.ANY_OBJ...))}, putsFunction)
+	RegisterFunction(
+		"raise",
+		object.MethodLayout{
+			ArgPattern:    object.Args(object.Arg(object.STRING_OBJ)),
+			ReturnPattern: object.Args(object.Arg(object.ERROR_OBJ)),
+		},
+		raiseFunction,
+	)
 
 	RegisterModule("Math", "", mathFunctions, mathProperties)
 	RegisterModule("HTTP", "", httpFunctions, httpProperties)