Sort package imports in codegen

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

Author: jfhamlin

pkg/codegen/TODO.txt

@@ -3,3 +3,25 @@
 - handle namespace requires/uses/etc.
 - handle let bindings that are shared across multiple vars
 - test repeated let bindings of the same name, where previous bindings are shadowed
+
+
+Handle
+- java.io.StringReader21 "java.io.StringReader"
+- Exception12 "Exception"
+- java.lang.annotation17 "java.lang.annotation"
+- LinkedBlockingQueue28 "LinkedBlockingQueue"
+- CompilerException29 "glojure.lang.Compiler/CompilerException"
+- BigInteger11 "BigInteger"
+- java.lang.UnsupportedOperationException14 "java.lang.UnsupportedOperationException"
+- ExceptionInfo15 "ExceptionInfo"
+- lang1 "github.com/glojurelang/glojure/pkg/lang"
+- java.lang6 "java.lang"
+- glojure.lang.LineNumberingPushbackReader19 "glojure.lang.LineNumberingPushbackReader"
+- java.util.concurrent.CountDownLatch25 "java.util.concurrent.CountDownLatch"
+- BigDecimal9 "BigDecimal"
+- java.util.concurrent8 "java.util.concurrent"
+- java.io.InputStreamReader20 "java.io.InputStreamReader"
+- java.util22 "java.util"
+- glojure.lang4 "glojure.lang"
+- Object16 "Object"
+- java.net30 "java.net"

pkg/codegen/codegen.go

@@ -1288,7 +1288,17 @@ import (
   "github.com/glojurelang/glojure/pkg/lang"
 `
 
-	for pkg, alias := range g.imports {
+	// sort the imports by their package name for deterministic output
+	keys := make([]string, 0, len(g.imports))
+	for k := range g.imports {
+		keys = append(keys, k)
+	}
+	sort.Slice(keys, func(i, j int) bool {
+		return g.imports[keys[i]] < g.imports[keys[j]]
+	})
+
+	for _, pkg := range keys {
+		alias := g.imports[pkg]
 		header += fmt.Sprintf("  %s \"%s\"\n", alias, pkg)
 	}