33 files changed, 185 insertions(+), 68 deletions(-)

M go.mod
M go.sum
M pkg/compiler/ast.go
M pkg/compiler/parser.go
M pkg/compiler/parser_test.go
M pkg/compiler/printer.go
M pkg/compiler/printer_test.go
A pkg/compiler/testdata/comment.snow
A pkg/compiler/testdata/comment.snow.err
A pkg/compiler/testdata/comment.snow.want
A pkg/compiler/testdata/comments.snow
A pkg/compiler/testdata/comments.snow.err
A pkg/compiler/testdata/comments.snow.want
A pkg/compiler/testdata/empty.snow.err
A pkg/compiler/testdata/empty.snow.want
A pkg/compiler/testdata/let.snow
A pkg/compiler/testdata/let.snow.err
A pkg/compiler/testdata/let.snow.want
A pkg/compiler/testdata/let_full.snow
A pkg/compiler/testdata/let_full.snow.err
A pkg/compiler/testdata/let_full.snow.want
A pkg/compiler/testdata/let_infer.snow
A pkg/compiler/testdata/let_infer.snow.err
A pkg/compiler/testdata/let_infer.snow.want
A pkg/compiler/testdata/var.snow
A pkg/compiler/testdata/var.snow.err
A pkg/compiler/testdata/var.snow.want
A pkg/compiler/testdata/var_full.snow
A pkg/compiler/testdata/var_full.snow.err
A pkg/compiler/testdata/var_full.snow.want
A pkg/compiler/testdata/var_infer.snow
A pkg/compiler/testdata/var_infer.snow.err
A pkg/compiler/testdata/var_infer.snow.want

@@ 2,4 2,7 @@ module git.sr.ht/~mna/snow
 
 go 1.13
 
-require golang.org/x/exp v0.0.0-20191129062945-2f5052295587
+require (
+	github.com/kylelemons/godebug v1.1.0
+	golang.org/x/exp v0.0.0-20191129062945-2f5052295587
+)

@@ 1,6 1,8 @@
 dmitri.shuralyov.com/gpu/mtl v0.0.0-20190408044501-666a987793e9/go.mod h1:H6x//7gZCb22OMCxBHrMx7a5I7Hp++hsVxbQ4BYO7hU=
 github.com/BurntSushi/xgb v0.0.0-20160522181843-27f122750802/go.mod h1:IVnqGOEym/WlBOVXweHU+Q+/VP0lqqI8lqeDx9IjBqo=
 github.com/go-gl/glfw/v3.3/glfw v0.0.0-20191125211704-12ad95a8df72/go.mod h1:tQ2UAYgL5IevRw8kRxooKSPJfGvJ9fJQFa0TUsXzTg8=
+github.com/kylelemons/godebug v1.1.0 h1:RPNrshWIDI6G2gRW9EHilWtl7Z6Sb1BR0xunSBf0SNc=
+github.com/kylelemons/godebug v1.1.0/go.mod h1:9/0rRGxNHcop5bhtWyNeEfOS8JIWk580+fNqagV/RAw=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20190510104115-cbcb75029529/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
 golang.org/x/exp v0.0.0-20190306152737-a1d7652674e8/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=

@@ 16,7 16,7 @@ func (f *file) Pos() gotoken.Pos {
 		min = f.stmts[0].Pos()
 	}
 	if len(f.comments) > 0 {
-		if p := f.comments[0].Pos(); p < min {
+		if p := f.comments[0].Pos(); p < min || !min.IsValid() {
 			min = p
 		}
 	}


@@ 29,7 29,7 @@ func (f *file) End() gotoken.Pos {
 		max = f.stmts[l-1].End()
 	}
 	if l := len(f.comments); l > 0 {
-		if p := f.comments[l-1].End(); p > max {
+		if p := f.comments[l-1].End(); p > max || !max.IsValid() {
 			max = p
 		}
 	}


@@ 57,7 57,7 @@ type fnSig struct {
 
 func (f *fnSig) Pos() gotoken.Pos { return f.lparen }
 func (f *fnSig) End() gotoken.Pos {
-	if f.rarrow == gotoken.NoPos {
+	if !f.rarrow.IsValid() {
 		return f.rparen + 1
 	}
 	return f.retTyp.End()


@@ 72,7 72,7 @@ type paramDef struct {
 
 func (p *paramDef) Pos() gotoken.Pos { return p.name.Pos() }
 func (p *paramDef) End() gotoken.Pos {
-	if p.comma != gotoken.NoPos {
+	if p.comma.IsValid() {
 		return p.comma + 1
 	}
 	return p.typ.End()

@@ 91,10 91,12 @@ func (p *parser) advance(to map[token]bool) {
 func (p *parser) parseFile() *file {
 	// TODO: scopes
 
-	// stop if we had errors scanning the first token, likely not a valid source file.
-	if p.errors.Len() != 0 {
-		return nil
-	}
+	/*
+		// stop if we had errors scanning the first token, likely not a valid source file.
+		if p.errors.Len() != 0 {
+			return nil
+		}
+	*/
 
 	var stmts []stmt
 	for p.tok != EOF {

@@ 2,13 2,19 @@ package compiler
 
 import (
 	"bytes"
-	"fmt"
+	"flag"
+	goscanner "go/scanner"
 	gotoken "go/token"
 	"io/ioutil"
+	"os"
 	"path/filepath"
 	"testing"
+
+	"github.com/kylelemons/godebug/diff"
 )
 
+var testUpdateParserTests = flag.Bool("test.update-parser-tests", false, "If set, replace expected parser test results with actual results.")
+
 func TestParser(t *testing.T) {
 	fis, err := ioutil.ReadDir("testdata")
 	if err != nil {


@@ 35,17 41,52 @@ func TestParser(t *testing.T) {
 			p.init(fset, fi.Name(), b)
 
 			f := p.parseFile()
-			if err := p.errors.Err(); err != nil {
-				t.Fatal(err)
-			}
-			fmt.Printf(">>>>\n%#v\n", f)
+			p.errors.RemoveMultiples()
+			parseErr := p.errors.Err()
+
+			var ebuf bytes.Buffer
+			goscanner.PrintError(&ebuf, parseErr)
 
 			var buf bytes.Buffer
 			pp := printer{w: &buf, withPos: true, withComments: true}
 			if err := pp.Print(f, p.file); err != nil {
 				t.Fatal(err)
 			}
-			t.Logf("\n%s\n", buf.String())
+
+			wantFile := filepath.Join("testdata", fi.Name()+".want")
+			errFile := filepath.Join("testdata", fi.Name()+".err")
+			if *testUpdateParserTests {
+				if err := ioutil.WriteFile(wantFile, buf.Bytes(), 0666); err != nil {
+					t.Fatal(err)
+				}
+
+				if err := ioutil.WriteFile(errFile, ebuf.Bytes(), 0666); err != nil {
+					t.Fatal(err)
+				}
+				return
+			}
+
+			// validate AST output
+			want, err := ioutil.ReadFile(wantFile)
+			if err != nil && !os.IsNotExist(err) {
+				t.Fatal(err)
+			}
+			t.Logf("got:\n%s\n", buf.String())
+			t.Logf("want:\n%s\n", string(want))
+			if patch := diff.Diff(buf.String(), string(want)); patch != "" {
+				t.Errorf("diff:\n%s\n", patch)
+			}
+
+			// validate errors output
+			ewant, err := ioutil.ReadFile(errFile)
+			if err != nil && !os.IsNotExist(err) {
+				t.Fatal(err)
+			}
+			t.Logf("got error(s):\n%s\n", ebuf.String())
+			t.Logf("want error(s):\n%s\n", string(ewant))
+			if patch := diff.Diff(ebuf.String(), string(ewant)); patch != "" {
+				t.Errorf("diff error(s):\n%s\n", patch)
+			}
 		})
 	}
 }

@@ 89,7 89,14 @@ func (p *printer) Visit(n node) visitor {
 	case *block:
 		p.printMsg("block", true)
 	case *varDef:
-		p.printMsg("var", true)
+		lbl := n.kw.String()
+		if n.colon.IsValid() {
+			lbl += ":"
+		}
+		if n.assign.IsValid() {
+			lbl += "="
+		}
+		p.printMsg(lbl, true)
 	case *returnStmt:
 		p.printMsg("return", true)
 	case *binaryExpr:


@@ 99,9 106,9 @@ func (p *printer) Visit(n node) visitor {
 	case *parenExpr:
 		p.printMsg("paren", true)
 	case *basicLit:
-		p.printMsg(fmt.Sprintf("%s [%q]", n.literal, n.value), true)
+		p.printMsg(fmt.Sprintf("%s [%s]", n.literal, n.value), true)
 	case *ident:
-		p.printMsg(fmt.Sprintf("ident [%q]", n.name), true)
+		p.printMsg(fmt.Sprintf("ident [%s]", n.name), true)
 	case *badStmt:
 		p.printMsg("bad stmt", true)
 	case *badExpr:

@@ 6,6 6,8 @@ import (
 	gotoken "go/token"
 	"strings"
 	"testing"
+
+	"github.com/kylelemons/godebug/diff"
 )
 
 func TestPrinter(t *testing.T) {


@@ 109,94 111,94 @@ func TestPrinter(t *testing.T) {
 
 	wantNoPos := `
 file
-    var
-      ident ["a"]
-      ident ["int"]
-      int ["1"]
+    var:=
+      ident [a]
+      ident [int]
+      int [1]
     fn
-      ident ["add"]
+      ident [add]
       sig
         param
-          ident ["x"]
-          ident ["int"]
+          ident [x]
+          ident [int]
         param
-          ident ["y"]
-          ident ["int"]
-        ident ["int"]
+          ident [y]
+          ident [int]
+        ident [int]
       block
         return
           binary [+]
-            ident ["x"]
-            ident ["y"]
+            ident [x]
+            ident [y]
 `
 	wantComments := `
 file
   comments
     comment [#abc]
     comment [#def]
-  var
-    ident ["a"]
-    ident ["int"]
-    int ["1"]
+  var:=
+    ident [a]
+    ident [int]
+    int [1]
   fn
-    ident ["add"]
+    ident [add]
     sig
       param
-        ident ["x"]
-        ident ["int"]
+        ident [x]
+        ident [int]
       param
-        ident ["y"]
-        ident ["int"]
-      ident ["int"]
+        ident [y]
+        ident [int]
+      ident [int]
     block
       return
         binary [+]
-          ident ["x"]
-          ident ["y"]
+          ident [x]
+          ident [y]
 `
 	wantShort := `
 file [0:69]
-    var [8:22]
-      ident ["a"] [12:13]
-      ident ["int"] [15:18]
-      int ["1"] [21:22]
+    var:= [8:22]
+      ident [a] [12:13]
+      ident [int] [15:18]
+      int [1] [21:22]
     fn [23:69]
-      ident ["add"] [26:29]
+      ident [add] [26:29]
       sig [30:51]
         param [31:38]
-          ident ["x"] [31:32]
-          ident ["int"] [34:37]
+          ident [x] [31:32]
+          ident [int] [34:37]
         param [39:45]
-          ident ["y"] [39:40]
-          ident ["int"] [42:45]
-        ident ["int"] [48:51]
+          ident [y] [39:40]
+          ident [int] [42:45]
+        ident [int] [48:51]
       block [52:69]
         return [56:67]
           binary [+] [64:67]
-            ident ["x"] [64:65]
-            ident ["y"] [66:67]
+            ident [x] [64:65]
+            ident [y] [66:67]
 `
 	wantLong := `
 file [test:1:1::1:70]
-    var [test:1:9::1:23]
-      ident ["a"] [test:1:13::1:14]
-      ident ["int"] [test:1:16::1:19]
-      int ["1"] [test:1:22::1:23]
+    var:= [test:1:9::1:23]
+      ident [a] [test:1:13::1:14]
+      ident [int] [test:1:16::1:19]
+      int [1] [test:1:22::1:23]
     fn [test:1:24::1:70]
-      ident ["add"] [test:1:27::1:30]
+      ident [add] [test:1:27::1:30]
       sig [test:1:31::1:52]
         param [test:1:32::1:39]
-          ident ["x"] [test:1:32::1:33]
-          ident ["int"] [test:1:35::1:38]
+          ident [x] [test:1:32::1:33]
+          ident [int] [test:1:35::1:38]
         param [test:1:40::1:46]
-          ident ["y"] [test:1:40::1:41]
-          ident ["int"] [test:1:43::1:46]
-        ident ["int"] [test:1:49::1:52]
+          ident [y] [test:1:40::1:41]
+          ident [int] [test:1:43::1:46]
+        ident [int] [test:1:49::1:52]
       block [test:1:53::1:70]
         return [test:1:57::1:68]
           binary [+] [test:1:65::1:68]
-            ident ["x"] [test:1:65::1:66]
-            ident ["y"] [test:1:67::1:68]
+            ident [x] [test:1:65::1:66]
+            ident [y] [test:1:67::1:68]
 `
 
 	cases := []struct {


@@ 225,8 227,8 @@ file [test:1:1::1:70]
 
 			want := strings.TrimSpace(c.want)
 			got := strings.TrimSpace(buf.String())
-			if want != got {
-				t.Fatalf("want:\n%s\ngot:\n%s\n", want, got)
+			if patch := diff.Diff(got, want); patch != "" {
+				t.Fatalf("diff:\n%s\n", patch)
 			}
 		})
 	}

@@ 0,0 1,1 @@
+# hello

@@ 0,0 1,3 @@
+file [0:7]
+  comments [0:7]
+    comment [# hello] [0:7]

@@ 0,0 1,10 @@
+# group a.1
+# group a.2
+  # group a.3
+
+# group a.4
+
+$
+
+# group b.1
+# group b.2

@@ 0,0 1,1 @@
+comments.snow:7:1: expected statement, found 'illegal'

@@ 0,0 1,10 @@
+file [0:79]
+  comments [0:50]
+    comment [# group a.1] [0:11]
+    comment [# group a.2] [12:23]
+    comment [# group a.3] [26:37]
+    comment [# group a.4] [39:50]
+  comments [55:78]
+    comment [# group b.1] [55:66]
+    comment [# group b.2] [67:78]
+  bad stmt [52:79]

@@ 0,0 1,1 @@
+file [-:-]

@@ 0,0 1,1 @@
+let x: int

@@ 0,0 1,4 @@
+file [0:10]
+  let: [0:10]
+    ident [x] [4:5]
+    ident [int] [7:10]

@@ 0,0 1,2 @@
+let x: string = "abc"
+

@@ 0,0 1,5 @@
+file [0:21]
+  let:= [0:21]
+    ident [x] [4:5]
+    ident [string] [7:13]
+    string ["abc"] [16:21]

@@ 0,0 1,1 @@
+let x = "a"

@@ 0,0 1,4 @@
+file [0:11]
+  let= [0:11]
+    ident [x] [4:5]
+    string ["a"] [8:11]

@@ 0,0 1,1 @@
+var x: int

@@ 0,0 1,4 @@
+file [0:10]
+  var: [0:10]
+    ident [x] [4:5]
+    ident [int] [7:10]

@@ 0,0 1,2 @@
+var x: int = 123
+

@@ 0,0 1,5 @@
+file [0:16]
+  var:= [0:16]
+    ident [x] [4:5]
+    ident [int] [7:10]
+    int [123] [13:16]

@@ 0,0 1,1 @@
+var x = 10

@@ 0,0 1,4 @@
+file [0:10]
+  var= [0:10]
+    ident [x] [4:5]
+    int [10] [8:10]