11 files changed, 40 insertions(+), 3 deletions(-)

M go.mod
M go.sum
M pkg/compiler/parser.go
M pkg/compiler/parser_test.go
M pkg/compiler/scanner.go
A pkg/compiler/testdata/fn.snow
A pkg/compiler/testdata/fn.snow.err
A pkg/compiler/testdata/fn.snow.want
A pkg/compiler/testdata/fn_add.snow.notyet
A pkg/compiler/testdata/fn_naked_return.snow.notyet
M pkg/grammar/grammar.ebnf

@@ 3,6 3,7 @@ module git.sr.ht/~mna/snow
 go 1.13
 
 require (
+	github.com/kr/pretty v0.1.0
 	github.com/kylelemons/godebug v1.1.0
 	golang.org/x/exp v0.0.0-20191129062945-2f5052295587
 )

@@ 1,6 1,11 @@
 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/kr/pretty v0.1.0 h1:L/CwN0zerZDmRFUapSPitk6f+Q3+0za1rQkzVuMiMFI=
+github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORNo=
+github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
+github.com/kr/text v0.1.0 h1:45sCR5RtlFHMR4UwH9sdQ5TC8v0qDQCHnXt+kaKSTVE=
+github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
 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=

@@ 100,7 100,7 @@ func (p *parser) parseFile() *file {
 
 	var stmts []stmt
 	for p.tok != EOF {
-		stmts = append(stmts, p.parseStmt())
+		stmts = append(stmts, p.parseStmt(true))
 	}
 
 	return &file{


@@ 109,7 109,14 @@ func (p *parser) parseFile() *file {
 	}
 }
 
-func (p *parser) parseStmt() stmt {
+func (p *parser) parseStmt(topLevel bool) stmt {
+	if !topLevel {
+		switch p.tok {
+		case Return:
+			return p.parseReturnStmt()
+		}
+	}
+
 	switch p.tok {
 	case Let, Var:
 		return p.parseVarDef()


@@ 123,6 130,14 @@ func (p *parser) parseStmt() stmt {
 	}
 }
 
+func (p *parser) parseReturnStmt() *returnStmt {
+	rs := &returnStmt{
+		ret: p.expect(Return),
+	}
+	// TODO: need auto-semicolons here, can't know if there's an expr after
+	return rs
+}
+
 func (p *parser) parseVarDef() *varDef {
 	vd := &varDef{
 		kw:    p.tok,


@@ 267,7 282,7 @@ func (p *parser) parseBlock() *block {
 func (p *parser) parseStmtList() []stmt {
 	var list []stmt
 	for p.tok != Rbrace && p.tok != EOF {
-		list = append(list, p.parseStmt())
+		list = append(list, p.parseStmt(false))
 	}
 	return list
 }

@@ 43,6 43,7 @@ func TestParser(t *testing.T) {
 			f := p.parseFile()
 			p.errors.RemoveMultiples()
 			parseErr := p.errors.Err()
+			//pretty.Print(f)
 
 			var ebuf bytes.Buffer
 			goscanner.PrintError(&ebuf, parseErr)

@@ 161,6 161,7 @@ func (s *scanner) ident() string {
 	for isLetter(s.cur) || isDigit(s.cur) {
 		s.next()
 	}
+	// TODO: allow single "!" or "?" at the end
 	return string(s.src[off:s.off])
 }
 

@@ 0,0 1,1 @@
+fn empty() { }

@@ 0,0 1,5 @@
+file [0:14]
+  fn [0:14]
+    ident [empty] [3:8]
+    sig [8:10]
+    block [11:14]

@@ 0,0 1,3 @@
+fn add(x: int, y: int) -> int {
+  return x + y
+}

@@ 0,0 1,4 @@
+fn print(x: int, y: string) {
+  x + y
+  return
+}

@@ 22,6 22,7 @@ ParamDef = ident ":" ident .
 FuncTrailer = "->" ident .
 Block = "{" { Stmt } "}" .
 
+// TODO: expression statement
 Stmt = VarDef | ReturnStmt .
 ReturnStmt = "return" [ Expr ] .