move to a direct byte code compiler (#8)

* chore: refactor to keep only the new parser and bytecode vm

* scanner: remove Token.value field

* scanner: remove scanner.kind field

* chore: move language specification in lang package

This avoid a cyclic dependency in scanner_test which can now use
the golang/GoSpec language specification for Go.

* clean code

* scanner: export scanner fields

Also parser now generate function calls, including externals.

* chore: fix lint issues

* parser: handle strings

* wip

* parser: implement support for 'if, else, else if' statements

Resolving labels in the compiler still in progress.

* parser: support if statements, improve compiler

* improve handling of functions

* improve support of local variables

* scanner: trim leading and trailing spaces

* fixes to make fibonacci work

* parser: improve README, fix function parameters parsing

1 files changed, 66 insertions, 0 deletions

diff --git a/parser/interpreter_test.go b/parser/interpreter_test.go
new file mode 100644
index 0000000..ee927a5
--- /dev/null
+++ b/parser/interpreter_test.go
@@ -0,0 +1,66 @@
+package parser_test
+
+import (
+	"fmt"
+	"log"
+	"testing"
+
+	"github.com/gnolang/parscan/lang/golang"
+	"github.com/gnolang/parscan/parser"
+	"github.com/gnolang/parscan/scanner"
+)
+
+var GoScanner *scanner.Scanner
+
+func init() {
+	log.SetFlags(log.Lshortfile)
+	GoScanner = scanner.NewScanner(golang.GoSpec)
+}
+
+func TestEval(t *testing.T) {
+	for _, test := range goTests {
+		test := test
+		t.Run("", func(t *testing.T) {
+			interp := parser.NewInterpreter(GoScanner)
+			errStr := ""
+			r, e := interp.Eval(test.src)
+			t.Log(r, e)
+			if e != nil {
+				errStr = e.Error()
+			}
+			if errStr != test.err {
+				t.Errorf("got error %#v, want error %#v", errStr, test.err)
+			}
+			if res := fmt.Sprintf("%v", r); test.err == "" && res != test.res {
+				t.Errorf("got %#v, want %#v", res, test.res)
+			}
+		})
+	}
+}
+
+var goTests = []struct {
+	src, res, err string
+}{
+	0:  {src: "", res: "<nil>"},
+	1:  {src: "1+2", res: "3"},
+	2:  {src: "1+", err: "block not terminated"},
+	3:  {src: "a := 1 + 2; b := 0; a + 1", res: "4"},
+	4:  {src: "1+(2+3)", res: "6"},
+	5:  {src: "(1+2)+3", res: "6"},
+	6:  {src: "(6+(1+2)+3)+5", res: "17"},
+	7:  {src: "(6+(1+2+3)+5", err: "1:1: block not terminated"},
+	8:  {src: "a := 2; a = 3; a", res: "3"},
+	9:  {src: "a := 0; if a == 0 { a = 2 } else { a = 1 }; a", res: "2"},
+	10: {src: "a := 0; if a == 1 { a = 2 } else { a = 1 }; a", res: "1"},
+	11: {src: "a := 0; if a == 1 { a = 2 } else if a == 0 { a = 3 } else { a = 1 }; a", res: "3"},
+	12: {src: "a := 0; if a == 1 { a = 2 } else if a == 2 { a = 3 } else { a = 1 }; a", res: "1"},
+	13: {src: "func f() int {return 2}; a := f(); a", res: "2"},
+	14: {src: "func f() int {return 2}; f()", res: "2"},
+	15: {src: "func f(a int) int {return a+2}; f(3)", res: "5"},
+	16: {src: "func f(a int) int {if a < 4 {a = 5}; return a }; f(3)", res: "5"},
+	17: {src: "func f(a int) int {return a+2}; 7 - f(3)", res: "2"},
+	18: {src: "func f(a int) int {return a+2}; f(5) - f(3)", res: "2"},
+	19: {src: "func f(a int) int {return a+2}; f(3) - 2", res: "3"},
+	20: {src: "func f(a int, b int, c int) int {return a+b-c} ; f(7, 1, 3)", res: "5"},
+	21: {src: "func f(a, b, c int) int {return a+b-c} ; f(7, 1, 3)", res: "5"},
+}