go/src/core/core.go

   1 package core
   2
   3 import (
   4     "errors"
   5     "io/ioutil"
   6     "fmt"
   7 )
   8
   9 import (
  10     . "types"
  11     "reader"
  12     "printer"
  13 )
  14
  15
  16 // String functions
  17
  18 func pr_str(a []MalType) (MalType, error) {
  19     return printer.Pr_list(a, true, "", "", " "), nil
  20 }
  21
  22 func str(a []MalType) (MalType, error) {
  23     return printer.Pr_list(a, false, "", "", ""), nil
  24 }
  25
  26 func prn(a []MalType) (MalType, error) {
  27     fmt.Println(printer.Pr_list(a, true, "", "", " "))
  28     return nil, nil
  29 }
  30
  31 func println(a []MalType) (MalType, error) {
  32     fmt.Println(printer.Pr_list(a, false, "", "", " "))
  33     return nil, nil
  34 }
  35
  36 func slurp(a []MalType) (MalType, error) {
  37     b, e := ioutil.ReadFile(a[0].(string))
  38     if e != nil { return nil, e }
  39     return string(b), nil
  40 }
  41
  42
  43 // Sequence functions
  44
  45 func empty_Q(a []MalType) (MalType, error) {
  46     switch obj := a[0].(type) {
  47     case List:   return len(obj.Val) == 0, nil
  48     case Vector: return len(obj.Val) == 0, nil
  49     case nil:    return true, nil
  50     default: return nil, errors.New("Count called on non-sequence")
  51     }
  52 }
  53
  54 func count(a []MalType) (MalType, error) {
  55     switch obj := a[0].(type) {
  56     case List:   return len(obj.Val), nil
  57     case Vector: return len(obj.Val), nil
  58     case nil:    return 0, nil
  59     default: return nil, errors.New("Count called on non-sequence")
  60     }
  61 }
  62
  63
  64 // core namespace
  65 var NS = map[string]MalType{
  66     "=": func(a []MalType) (MalType, error) {
  67             return Equal_Q(a[0], a[1]), nil },
  68
  69     "pr-str": func(a []MalType) (MalType, error) { return pr_str(a) },
  70     "str": func(a []MalType) (MalType, error) { return str(a) },
  71     "prn": func(a []MalType) (MalType, error) { return prn(a) },
  72     "println": func(a []MalType) (MalType, error) { return println(a) },
  73     "read-string":  func(a []MalType) (MalType, error) {
  74             return reader.Read_str(a[0].(string)) },
  75     "slurp": slurp,
  76
  77     "<": func(a []MalType) (MalType, error) {
  78             return a[0].(int) < a[1].(int), nil },
  79     "<=": func(a []MalType) (MalType, error) {
  80             return a[0].(int) <= a[1].(int), nil },
  81     ">": func(a []MalType) (MalType, error) {
  82             return a[0].(int) > a[1].(int), nil },
  83     ">=": func(a []MalType) (MalType, error) {
  84             return a[0].(int) >= a[1].(int), nil },
  85     "+": func(a []MalType) (MalType, error) {
  86             return a[0].(int) + a[1].(int), nil },
  87     "-": func(a []MalType) (MalType, error) {
  88             return a[0].(int) - a[1].(int), nil },
  89     "*": func(a []MalType) (MalType, error) {
  90             return a[0].(int) * a[1].(int), nil },
  91     "/": func(a []MalType) (MalType, error) {
  92             return a[0].(int) / a[1].(int), nil },
  93
  94     "list": func(a []MalType) (MalType, error) {
  95             return List{a}, nil },
  96     "list?": func(a []MalType) (MalType, error) {
  97             return List_Q(a[0]), nil },
  98
  99     "empty?": empty_Q,
 100     "count": count,
 101     }