go: add readline.go that wraps libreadline/libedit

13 files changed, 102 insertions, 60 deletions

diff --git a/go/Makefile b/go/Makefile
index 729d2cc..18faa4f 100644
--- a/go/Makefile
+++ b/go/Makefile
@@ -2,7 +2,8 @@ export GOPATH := $(dir $(abspath $(lastword $(MAKEFILE_LIST))))
 
 #####################
 
-SOURCES_BASE = src/types/types.go src/reader/reader.go src/printer/printer.go \
+SOURCES_BASE = src/types/types.go src/readline/readline.go \
+	       src/reader/reader.go src/printer/printer.go \
 	       src/env/env.go src/core/core.go
 SOURCES_LISP = src/stepA_more/stepA_more.go
 SOURCES = $(SOURCES_BASE) $(SOURCES_LISP)
diff --git a/go/src/core/core.go b/go/src/core/core.go
index b3961e1..cd63930 100644
--- a/go/src/core/core.go
+++ b/go/src/core/core.go
@@ -10,6 +10,7 @@ import (
     . "types"
     "reader"
     "printer"
+    "readline"
 )
 
 // Errors/Exceptions
@@ -150,6 +151,8 @@ var NS = map[string]MalType{
     "read-string":  func(a []MalType) (MalType, error) {
             return reader.Read_str(a[0].(string)) },
     "slurp": slurp,
+    "readline": func(a []MalType) (MalType, error) {
+            return readline.Readline(a[0].(string)) },
 
     "<": func(a []MalType) (MalType, error) {
             return a[0].(int) < a[1].(int), nil },
diff --git a/go/src/readline/readline.go b/go/src/readline/readline.go
new file mode 100644
index 0000000..2777cb4
--- /dev/null
+++ b/go/src/readline/readline.go
@@ -0,0 +1,70 @@
+package readline
+
+/*
+// IMPORTANT: choose one
+#cgo LDFLAGS: -ledit
+//#cgo LDFLAGS: -lreadline // NOTE: libreadline is GPL
+
+// free()
+#include <stdlib.h>
+// readline()
+#include <readline/readline.h>
+// add_history()
+#include <readline/history.h>
+*/
+import "C"
+
+import (
+    "errors"
+    "unsafe"
+    "strings"
+    "io/ioutil"
+    "os"
+    "path/filepath"
+    "fmt"
+)
+
+var HISTORY_FILE = ".mal-history"
+
+var rl_history_loaded = false
+
+func Readline(prompt string) (string, error) {
+    history_path := filepath.Join(os.Getenv("HOME"), "/", HISTORY_FILE)
+
+    if !rl_history_loaded {
+        rl_history_loaded = true
+        content, e := ioutil.ReadFile(history_path)
+        if e != nil { return "", e }
+
+        for _, add_line := range strings.Split(string(content), "\n") {
+            if add_line == "" { continue }
+            c_add_line := C.CString(add_line)
+            C.add_history(c_add_line)
+            C.free(unsafe.Pointer(c_add_line))
+        }
+    }
+
+
+    c_prompt := C.CString(prompt)
+    defer C.free(unsafe.Pointer(c_prompt))
+
+    c_line := C.readline(c_prompt)
+    defer C.free(unsafe.Pointer(c_line))
+    line := C.GoString(c_line)
+
+    if c_line == nil {
+        return "", errors.New("C.readline call failed")
+    }
+    C.add_history(c_line)
+
+    // append to file
+    f, e := os.OpenFile(history_path, os.O_APPEND|os.O_WRONLY, 0600) 
+    if e == nil {
+        defer f.Close()
+
+        _, e = f.WriteString(line+"\n")
+        if e != nil { fmt.Printf("error writing to history") }
+    }
+
+    return line, nil
+}
diff --git a/go/src/step0_repl/step0_repl.go b/go/src/step0_repl/step0_repl.go
index 1203213..2e4c47c 100644
--- a/go/src/step0_repl/step0_repl.go
+++ b/go/src/step0_repl/step0_repl.go
@@ -1,12 +1,14 @@
 package main
 
 import (
-    "bufio"
     "fmt"
-    "os"
     "strings"
 )
 
+import (
+    "readline"
+)
+
 // read
 func READ(str string) string {
     return str
@@ -28,11 +30,9 @@ func rep(str string) string {
 }
 
 func main() {
-    reader := bufio.NewReader(os.Stdin);
     // repl loop
     for {
-        fmt.Print("user> ");
-        text, err := reader.ReadString('\n');
+        text, err := readline.Readline("user> ")
         text = strings.TrimRight(text, "\n");
         if (err != nil) {
             return
diff --git a/go/src/step1_read_print/step1_read_print.go b/go/src/step1_read_print/step1_read_print.go
index edd8c42..e008ed5 100644
--- a/go/src/step1_read_print/step1_read_print.go
+++ b/go/src/step1_read_print/step1_read_print.go
@@ -1,14 +1,12 @@
 package main
 
 import (
-    "bufio"
-    //"io"
     "fmt"
-    "os"
     "strings"
 )
 
 import (
+    "readline"
     . "types"
     "reader"
     "printer"
@@ -41,11 +39,9 @@ func rep(str string) (MalType, error) {
 }
 
 func main() {
-    rdr := bufio.NewReader(os.Stdin);
     // repl loop
     for {
-        fmt.Print("user> ");
-        text, err := rdr.ReadString('\n');
+        text, err := readline.Readline("user> ")
         text = strings.TrimRight(text, "\n");
         if (err != nil) {
             return
diff --git a/go/src/step2_eval/step2_eval.go b/go/src/step2_eval/step2_eval.go
index 3ab35ed..9b3aa28 100644
--- a/go/src/step2_eval/step2_eval.go
+++ b/go/src/step2_eval/step2_eval.go
@@ -1,15 +1,13 @@
 package main
 
 import (
-    "bufio"
-    //"io"
     "fmt"
-    "os"
     "strings"
     "errors"
 )
 
 import (
+    "readline"
     . "types"
     "reader"
     "printer"
@@ -110,11 +108,9 @@ func rep(str string) (MalType, error) {
 }
 
 func main() {
-    rdr := bufio.NewReader(os.Stdin);
     // repl loop
     for {
-        fmt.Print("user> ");
-        text, err := rdr.ReadString('\n');
+        text, err := readline.Readline("user> ")
         text = strings.TrimRight(text, "\n");
         if (err != nil) {
             return
diff --git a/go/src/step3_env/step3_env.go b/go/src/step3_env/step3_env.go
index 68a8f0c..7e45a39 100644
--- a/go/src/step3_env/step3_env.go
+++ b/go/src/step3_env/step3_env.go
@@ -1,15 +1,13 @@
 package main
 
 import (
-    "bufio"
-    //"io"
     "fmt"
-    "os"
     "strings"
     "errors"
 )
 
 import (
+    "readline"
     . "types"
     "reader"
     "printer"
@@ -138,11 +136,9 @@ func main() {
     repl_env.Set("/", func(a []MalType) (MalType, error) {
         return a[0].(int) / a[1].(int), nil })
 
-    rdr := bufio.NewReader(os.Stdin);
     // repl loop
     for {
-        fmt.Print("user> ");
-        text, err := rdr.ReadString('\n');
+        text, err := readline.Readline("user> ")
         text = strings.TrimRight(text, "\n");
         if (err != nil) {
             return
diff --git a/go/src/step4_if_fn_do/step4_if_fn_do.go b/go/src/step4_if_fn_do/step4_if_fn_do.go
index 7a91a2b..760919b 100644
--- a/go/src/step4_if_fn_do/step4_if_fn_do.go
+++ b/go/src/step4_if_fn_do/step4_if_fn_do.go
@@ -1,15 +1,13 @@
 package main
 
 import (
-    "bufio"
-    //"io"
     "fmt"
-    "os"
     "strings"
     "errors"
 )
 
 import (
+    "readline"
     . "types"
     "reader"
     "printer"
@@ -162,11 +160,9 @@ func main() {
     // core.mal: defined using the language itself
     rep("(def! not (fn* (a) (if a false true)))")
 
-    rdr := bufio.NewReader(os.Stdin);
     // repl loop
     for {
-        fmt.Print("user> ");
-        text, err := rdr.ReadString('\n');
+        text, err := readline.Readline("user> ")
         text = strings.TrimRight(text, "\n");
         if (err != nil) {
             return
diff --git a/go/src/step5_tco/step5_tco.go b/go/src/step5_tco/step5_tco.go
index a15d9e5..c7c2ab5 100644
--- a/go/src/step5_tco/step5_tco.go
+++ b/go/src/step5_tco/step5_tco.go
@@ -1,15 +1,13 @@
 package main
 
 import (
-    "bufio"
-    //"io"
     "fmt"
-    "os"
     "strings"
     "errors"
 )
 
 import (
+    "readline"
     . "types"
     "reader"
     "printer"
@@ -172,11 +170,9 @@ func main() {
     // core.mal: defined using the language itself
     rep("(def! not (fn* (a) (if a false true)))")
 
-    rdr := bufio.NewReader(os.Stdin);
     // repl loop
     for {
-        fmt.Print("user> ");
-        text, err := rdr.ReadString('\n');
+        text, err := readline.Readline("user> ")
         text = strings.TrimRight(text, "\n");
         if (err != nil) {
             return
diff --git a/go/src/step6_file/step6_file.go b/go/src/step6_file/step6_file.go
index 205b597..056fe39 100644
--- a/go/src/step6_file/step6_file.go
+++ b/go/src/step6_file/step6_file.go
@@ -1,15 +1,14 @@
 package main
 
 import (
-    "bufio"
-    //"io"
     "fmt"
-    "os"
     "strings"
     "errors"
+    "os"
 )
 
 import (
+    "readline"
     . "types"
     "reader"
     "printer"
@@ -187,11 +186,9 @@ func main() {
         os.Exit(0)
     }
 
-    rdr := bufio.NewReader(os.Stdin);
     // repl loop
     for {
-        fmt.Print("user> ");
-        text, err := rdr.ReadString('\n');
+        text, err := readline.Readline("user> ")
         text = strings.TrimRight(text, "\n");
         if (err != nil) {
             return
diff --git a/go/src/step7_quote/step7_quote.go b/go/src/step7_quote/step7_quote.go
index 4083354..68c2a85 100644
--- a/go/src/step7_quote/step7_quote.go
+++ b/go/src/step7_quote/step7_quote.go
@@ -1,15 +1,14 @@
 package main
 
 import (
-    "bufio"
-    //"io"
     "fmt"
-    "os"
     "strings"
     "errors"
+    "os"
 )
 
 import (
+    "readline"
     . "types"
     "reader"
     "printer"
@@ -220,11 +219,9 @@ func main() {
         os.Exit(0)
     }
 
-    rdr := bufio.NewReader(os.Stdin);
     // repl loop
     for {
-        fmt.Print("user> ");
-        text, err := rdr.ReadString('\n');
+        text, err := readline.Readline("user> ")
         text = strings.TrimRight(text, "\n");
         if (err != nil) {
             return
diff --git a/go/src/step8_macros/step8_macros.go b/go/src/step8_macros/step8_macros.go
index 6735275..82572d3 100644
--- a/go/src/step8_macros/step8_macros.go
+++ b/go/src/step8_macros/step8_macros.go
@@ -1,15 +1,14 @@
 package main
 
 import (
-    "bufio"
-    //"io"
     "fmt"
-    "os"
     "strings"
     "errors"
+    "os"
 )
 
 import (
+    "readline"
     . "types"
     "reader"
     "printer"
@@ -259,11 +258,9 @@ func main() {
         os.Exit(0)
     }
 
-    rdr := bufio.NewReader(os.Stdin);
     // repl loop
     for {
-        fmt.Print("user> ");
-        text, err := rdr.ReadString('\n');
+        text, err := readline.Readline("user> ")
         text = strings.TrimRight(text, "\n");
         if (err != nil) {
             return
diff --git a/go/src/stepA_more/stepA_more.go b/go/src/stepA_more/stepA_more.go
index 2532cfe..be693f6 100644
--- a/go/src/stepA_more/stepA_more.go
+++ b/go/src/stepA_more/stepA_more.go
@@ -1,15 +1,14 @@
 package main
 
 import (
-    "bufio"
-    //"io"
     "fmt"
-    "os"
     "strings"
     "errors"
+    "os"
 )
 
 import (
+    "readline"
     . "types"
     "reader"
     "printer"
@@ -281,11 +280,9 @@ func main() {
         os.Exit(0)
     }
 
-    rdr := bufio.NewReader(os.Stdin);
     // repl loop
     for {
-        fmt.Print("user> ");
-        text, err := rdr.ReadString('\n');
+        text, err := readline.Readline("user> ")
         text = strings.TrimRight(text, "\n");
         if (err != nil) {
             return