Add reader support for shebang-style comments

Signed-off-by: James Hamlin <jfhamlin@gmail.com>

Author: jfhamlin

pkg/reader/reader.go

@@ -937,6 +937,18 @@ func (r *Reader) readDispatch() (interface{}, error) {
 		return r.readExpr()
 	case '#':
 		return r.readSymbolicValue()
+	case '!':
+		// comment, discard until end of line
+		for {
+			rn, _, err := r.rs.ReadRune()
+			if err != nil {
+				return nil, r.error("error reading input: %w", err)
+			}
+			if rn == '\n' {
+				break
+			}
+		}
+		return r.readExpr()
 	default:
 		return nil, r.error("invalid dispatch character: %c", rn)
 	}

pkg/reader/testdata/clj-cache/read/7cf33476e7cff8b85c6eff7cd370f29253b2121045ac88f190714c42e61648b1.glj

@@ -0,0 +1,2 @@
+true
+291

pkg/reader/testdata/clj-cache/read/9466e130e88346e09e754f11f5539093f6df5223fe9922c21323ebab98fd518b.glj

@@ -0,0 +1,2 @@
+true
+1.0E10

pkg/reader/testdata/clj-cache/read/bfd59979737de1a540673045c3adb336332c2c205d2c5fbaff6b1c7a9f3fc9ef.glj

@@ -0,0 +1,2 @@
+true
+42

pkg/reader/testdata/clj-cache/read/c00e2650a826a4886c2bab00b70f6f3a00f8e1590c8cadc560ef493c3562028c.glj

@@ -0,0 +1,2 @@
+true
+0M

pkg/reader/testdata/clj-equiv-cache/efe5931ea5c44cd13420973e881027e0261414ca43a4872137e3508ebff9ca58

@@ -0,0 +1 @@
+true

pkg/reader/testdata/reader/shebang.glj

@@ -0,0 +1,2 @@
+#! this is treated as a comment
+42

pkg/reader/testdata/reader/shebang.out

@@ -0,0 +1 @@
+42