Fix IL generation error handling being unreliable

4 files changed, 7 insertions, 17 deletions

diff --git a/cer.go b/cer.go
index 51d9f29..255e453 100644
--- a/cer.go
+++ b/cer.go
@@ -11,17 +11,10 @@ package main
 import (
 	"fmt"
 	"os"
-	"sync"
 )
 
-var wg sync.WaitGroup
-
 func main() {
-	wg.Add(3)
-
-	errs := make(chan error)
-
-	go readErrs(errs)
+	errs := make(chan error, 1)
 
 	toks := make(chan token, 1024)
 	go lex(os.Stdin, toks, errs)
@@ -40,10 +33,9 @@ func main() {
 
 	go generate(<-root, os.Stdout, errs)
 
-	wg.Wait()
-}
-
-func readErrs(errs <-chan error) {
-	fmt.Fprintln(os.Stderr, <-errs)
-	os.Exit(1)
+	err := <-errs
+	if err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
 }
diff --git a/generate.go b/generate.go
index f09ec42..a32040a 100644
--- a/generate.go
+++ b/generate.go
@@ -58,7 +58,7 @@ func (i invalidToplevel) Error() string {
 }
 
 func generate(root *rootExpr, w io.Writer, errs chan<- error) {
-	defer wg.Done()
+	defer close(errs)
 
 	for _, toplevel := range root.toplevels {
 		if err := generateToplevel(toplevel, w); err != nil {
diff --git a/lex.go b/lex.go
index 621ed01..d4a4e30 100644
--- a/lex.go
+++ b/lex.go
@@ -25,7 +25,6 @@ func lex(src *os.File, tokens chan<- token, errs chan<- error) {
 		tok, err := readToken(br, &line)
 		if err != nil {
 			if err == io.EOF {
-				wg.Done()
 				return
 			}
 
diff --git a/parse.go b/parse.go
index 4983c65..b204468 100644
--- a/parse.go
+++ b/parse.go
@@ -65,7 +65,6 @@ func (t *tokens) mustMatch(kind tokenKind) error {
 }
 
 func parse(toks *tokens, root chan<- *rootExpr, errs chan<- error) {
-	defer wg.Done()
 	root <- parseRoot(toks, errs)
 }