go: step1_read_print print working.

5 files changed, 44 insertions, 7 deletions

diff --git a/go/Makefile b/go/Makefile
index 076a7aa..463fd12 100644
--- a/go/Makefile
+++ b/go/Makefile
@@ -2,7 +2,7 @@ export GOPATH := $(dir $(abspath $(lastword $(MAKEFILE_LIST))))
 
 #####################
 
-SOURCES_BASE = src/types/types.go src/reader/reader.go
+SOURCES_BASE = src/types/types.go src/reader/reader.go src/printer/printer.go
 SOURCES_LISP = src/step1_read_print/step1_read_print.go
 SOURCES = $(SOURCES_BASE) $(SOURCES_LISP)
 
diff --git a/go/src/printer/printer.go b/go/src/printer/printer.go
new file mode 100644
index 0000000..83d4c84
--- /dev/null
+++ b/go/src/printer/printer.go
@@ -0,0 +1,35 @@
+package printer
+
+import (
+    "fmt"
+    "strings"
+)
+
+import (
+    "types"
+)
+
+func Pr_str(obj types.MalType, print_readably bool) string {
+    switch tobj := obj.(type) {
+    case types.List:
+        str_list := make([]string, 0, len(tobj.Val))
+        for _, e := range tobj.Val {
+            str_list = append(str_list, Pr_str(e, print_readably))
+        }
+        return "(" + strings.Join(str_list, " ") + ")"
+    case string:
+        if print_readably {
+            // TODO: quote backslash, quote, and newline
+            return `"` + fmt.Sprintf("%v", obj) + `"`
+        } else {
+            return fmt.Sprintf("%v", obj)
+        }
+    case types.Symbol:
+        return tobj.Val
+    case nil:
+        return "nil"
+    default:
+        return fmt.Sprintf("%v", obj)
+    }
+    return "<printed>"
+}
diff --git a/go/src/reader/reader.go b/go/src/reader/reader.go
index 3222d6f..6a08840 100644
--- a/go/src/reader/reader.go
+++ b/go/src/reader/reader.go
@@ -29,7 +29,7 @@ func (tr *TokenReader) next() *string {
 }
 
 func (tr *TokenReader) peek() *string {
-    if tr.position > len(tr.tokens) { return nil }
+    if tr.position >= len(tr.tokens) { return nil }
     return &tr.tokens[tr.position]
 }
 
@@ -79,8 +79,9 @@ func read_list(rdr Reader) (types.MalType, error) {
         return nil, errors.New("expected '('")
     }
     token = rdr.peek()
-    for ; token != nil && *token != ")" ; token = rdr.peek() {
+    for ; true ; token = rdr.peek() {
         if token == nil { return nil, errors.New("exepected ')', got EOF") }
+        if *token == ")" { break }
         f, e := read_form(rdr)
         if e != nil { return nil, e }
         ast_list = append(ast_list, f)
diff --git a/go/src/step1_read_print/step1_read_print.go b/go/src/step1_read_print/step1_read_print.go
index 60a06cb..1f020af 100644
--- a/go/src/step1_read_print/step1_read_print.go
+++ b/go/src/step1_read_print/step1_read_print.go
@@ -11,6 +11,7 @@ import (
 import (
     "types"
     "reader"
+    "printer"
 )
 
 // read
@@ -25,7 +26,7 @@ func EVAL(ast types.MalType, env string) (types.MalType, error) {
 
 // print
 func PRINT(exp types.MalType) (types.MalType, error) {
-    return exp, nil
+    return printer.Pr_str(exp, true), nil
 }
 
 // repl
@@ -55,6 +56,6 @@ func main() {
             fmt.Printf("Error: %v\n", e)
             continue
         }
-        fmt.Printf("%#v\n", out)
+        fmt.Printf("%v\n", out)
     }
 }
diff --git a/tests/step1_read_print.mal b/tests/step1_read_print.mal
index 0c715de..7772de9 100644
--- a/tests/step1_read_print.mal
+++ b/tests/step1_read_print.mal
@@ -73,8 +73,8 @@ abc-def
 ;=>{"a" {"b" {"cde" 3}}}
 
 ;; Test commas as whitespace
-[1 2, 3,,,,],,
-;=>[1 2 3]
+(1 2, 3,,,,),,
+;=>(1 2 3)
 
 ;;
 ;; Testing reader errors