go: add step4_if_fn_do

1 files changed, 90 insertions, 0 deletions

diff --git a/go/src/core/core.go b/go/src/core/core.go
new file mode 100644
index 0000000..9df71a6
--- /dev/null
+++ b/go/src/core/core.go
@@ -0,0 +1,90 @@
+package core
+
+import (
+    "errors"
+    "fmt"
+)
+
+import (
+    . "types"
+    "printer"
+)
+
+
+// String functions
+
+func pr_str(a []MalType) (MalType, error) {
+    return printer.Pr_list(a, true, "", "", " "), nil
+}
+
+func str(a []MalType) (MalType, error) {
+    return printer.Pr_list(a, false, "", "", ""), nil
+}
+
+func prn(a []MalType) (MalType, error) {
+    fmt.Println(printer.Pr_list(a, true, "", "", " "))
+    return nil, nil
+}
+
+func println(a []MalType) (MalType, error) {
+    fmt.Println(printer.Pr_list(a, false, "", "", " "))
+    return nil, nil
+}
+
+
+// Sequence functions
+
+func empty_Q(a []MalType) (MalType, error) {
+    switch obj := a[0].(type) {
+    case List:   return len(obj.Val) == 0, nil
+    case Vector: return len(obj.Val) == 0, nil
+    case nil:    return true, nil
+    default: return nil, errors.New("Count called on non-sequence")
+    }
+}
+
+func count(a []MalType) (MalType, error) {
+    switch obj := a[0].(type) {
+    case List:   return len(obj.Val), nil
+    case Vector: return len(obj.Val), nil
+    case nil:    return 0, nil
+    default: return nil, errors.New("Count called on non-sequence")
+    }
+}
+
+
+// core namespace
+var NS = map[string]MalType{
+    "=": func(a []MalType) (MalType, error) {
+            return Equal_Q(a[0], a[1]), nil },
+
+    "pr-str": func(a []MalType) (MalType, error) { return pr_str(a) },
+    "str": func(a []MalType) (MalType, error) { return str(a) },
+    "prn": func(a []MalType) (MalType, error) { return prn(a) },
+    "println": func(a []MalType) (MalType, error) { return println(a) },
+
+    "<": func(a []MalType) (MalType, error) {
+            return a[0].(int) < a[1].(int), nil },
+    "<=": func(a []MalType) (MalType, error) {
+            return a[0].(int) <= a[1].(int), nil },
+    ">": func(a []MalType) (MalType, error) {
+            return a[0].(int) > a[1].(int), nil },
+    ">=": func(a []MalType) (MalType, error) {
+            return a[0].(int) >= a[1].(int), nil },
+    "+": func(a []MalType) (MalType, error) {
+            return a[0].(int) + a[1].(int), nil },
+    "-": func(a []MalType) (MalType, error) {
+            return a[0].(int) - a[1].(int), nil },
+    "*": func(a []MalType) (MalType, error) {
+            return a[0].(int) * a[1].(int), nil },
+    "/": func(a []MalType) (MalType, error) {
+            return a[0].(int) / a[1].(int), nil },
+
+    "list": func(a []MalType) (MalType, error) {
+            return List{a}, nil },
+    "list?": func(a []MalType) (MalType, error) {
+            return List_Q(a[0]), nil },
+
+    "empty?": empty_Q,
+    "count": count,
+    }