diff --git a/.gitignore b/.gitignore
index 7cb4ef520..4a6282e5f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,5 +3,5 @@ bindata.go
 play
 .vscode
 .idea
-a_*.go
+core/a_*.go
 
diff --git a/circle.yml b/circle.yml
index 7d7c4300d..db0a7999f 100644
--- a/circle.yml
+++ b/circle.yml
@@ -5,7 +5,6 @@ dependencies:
     - mkdir -p ~/.go_workspace/src/github.com/${CIRCLE_PROJECT_USERNAME}
     - ln -s ${HOME}/${CIRCLE_PROJECT_REPONAME} ${HOME}/.go_workspace/src/github.com/${CIRCLE_PROJECT_USERNAME}/${CIRCLE_PROJECT_REPONAME}
     - go get -d -v github.com/chzyer/readline
-    - if [ ! -e ~/bin/joker ]; then wget -O ~/joker.zip https://github.com/candid82/joker/releases/download/v0.7.2/joker-0.7.2-linux-amd64.zip && unzip ~/joker.zip -d ~/bin; fi
     - go generate -v ./...
     - go build -v
     - ./linter-tests.sh
diff --git a/core/object.go b/core/object.go
index e80615369..468fa35e5 100644
--- a/core/object.go
+++ b/core/object.go
@@ -1,7 +1,6 @@
 //go:generate go run gen_data/gen_data.go
 //go:generate go run gen/gen_types.go assert Comparable *Vector Char String Symbol Keyword Regex Bool Number Seqable Callable *Type Meta Int Stack Map Set Associative Reversible Named Comparator *Ratio *Namespace *Var Error *Fn Deref *Atom Ref KVReduce Pending
 //go:generate go run gen/gen_types.go info *List *ArrayMapSeq *ArrayMap *HashMap *ExInfo *Fn *Var Nil *Ratio *BigInt *BigFloat Char Double Int Bool Keyword Regex Symbol String *LazySeq *MappingSeq *ArraySeq *ConsSeq *NodeSeq *ArrayNodeSeq *MapSet *Vector *VectorSeq *VectorRSeq
-//go:generate ../std/generate-std.sh
 
 package core
 
diff --git a/std/base64/a_base64.go b/std/base64/a_base64.go
new file mode 100644
index 000000000..b7b6e1afd
--- /dev/null
+++ b/std/base64/a_base64.go
@@ -0,0 +1,37 @@
+// This file is generated by generate-std.joke script. Do not edit manually!
+
+package base64
+
+import (
+  
+  . "github.com/candid82/joker/core"
+)
+
+var base64Namespace = GLOBAL_ENV.EnsureNamespace(MakeSymbol("joker.base64"))
+
+var decode_string_ Proc = func(args []Object) Object {
+  c := len(args)
+  switch  {
+  case c == 1:
+    
+    s := ExtractString(args, 0)
+    res := base64DecodeString(s)
+    return MakeString(res)
+
+  default:
+    PanicArity(c)
+  }
+  return NIL
+}
+
+
+func init() {
+
+base64Namespace.ResetMeta(MakeMeta(nil, "Implements base64 encoding as specified by RFC 4648.", "1.0"))
+
+base64Namespace.InternVar("decode-string", decode_string_,
+  MakeMeta(
+    NewListFrom(NewVectorFrom(MakeSymbol("s"))),
+    `Returns the bytes represented by the base64 string s.`, "1.0"))
+
+}
diff --git a/std/json/a_json.go b/std/json/a_json.go
new file mode 100644
index 000000000..f05d9e6f3
--- /dev/null
+++ b/std/json/a_json.go
@@ -0,0 +1,57 @@
+// This file is generated by generate-std.joke script. Do not edit manually!
+
+package json
+
+import (
+  
+  . "github.com/candid82/joker/core"
+)
+
+var jsonNamespace = GLOBAL_ENV.EnsureNamespace(MakeSymbol("joker.json"))
+
+var write_string_ Proc = func(args []Object) Object {
+  c := len(args)
+  switch  {
+  case c == 1:
+    
+    v := ExtractObject(args, 0)
+    res := writeString(v)
+    return res
+
+  default:
+    PanicArity(c)
+  }
+  return NIL
+}
+
+var read_string_ Proc = func(args []Object) Object {
+  c := len(args)
+  switch  {
+  case c == 1:
+    
+    s := ExtractString(args, 0)
+    res := readString(s)
+    return res
+
+  default:
+    PanicArity(c)
+  }
+  return NIL
+}
+
+
+func init() {
+
+jsonNamespace.ResetMeta(MakeMeta(nil, "Implements encoding and decoding of JSON as defined in RFC 4627.", "1.0"))
+
+jsonNamespace.InternVar("write-string", write_string_,
+  MakeMeta(
+    NewListFrom(NewVectorFrom(MakeSymbol("v"))),
+    `Returns the JSON encoding of v.`, "1.0"))
+
+jsonNamespace.InternVar("read-string", read_string_,
+  MakeMeta(
+    NewListFrom(NewVectorFrom(MakeSymbol("s"))),
+    `Parses the JSON-encoded data and return the result as a Joker value.`, "1.0"))
+
+}
diff --git a/std/os/a_os.go b/std/os/a_os.go
new file mode 100644
index 000000000..8441780ee
--- /dev/null
+++ b/std/os/a_os.go
@@ -0,0 +1,101 @@
+// This file is generated by generate-std.joke script. Do not edit manually!
+
+package os
+
+import (
+  "os"
+  . "github.com/candid82/joker/core"
+)
+
+var osNamespace = GLOBAL_ENV.EnsureNamespace(MakeSymbol("joker.os"))
+
+var sh_ Proc = func(args []Object) Object {
+  c := len(args)
+  switch  {
+  case true:
+    CheckArity(args, 1,999)
+    name := ExtractString(args, 0)
+    arguments := ExtractStrings(args, 1)
+    res := sh(name, arguments)
+    return res
+
+  default:
+    PanicArity(c)
+  }
+  return NIL
+}
+
+var env_ Proc = func(args []Object) Object {
+  c := len(args)
+  switch  {
+  case c == 0:
+    
+    
+    res := env()
+    return res
+
+  default:
+    PanicArity(c)
+  }
+  return NIL
+}
+
+var args_ Proc = func(args []Object) Object {
+  c := len(args)
+  switch  {
+  case c == 0:
+    
+    
+    res := commandArgs()
+    return res
+
+  default:
+    PanicArity(c)
+  }
+  return NIL
+}
+
+var exit_ Proc = func(args []Object) Object {
+  c := len(args)
+  switch  {
+  case c == 1:
+    
+    code := ExtractInt(args, 0)
+    res := NIL; os.Exit(code)
+    return res
+
+  default:
+    PanicArity(c)
+  }
+  return NIL
+}
+
+
+func init() {
+
+osNamespace.ResetMeta(MakeMeta(nil, "Provides a platform-independent interface to operating system functionality.", "1.0"))
+
+osNamespace.InternVar("sh", sh_,
+  MakeMeta(
+    NewListFrom(NewVectorFrom(MakeSymbol("name"), MakeSymbol("&"), MakeSymbol("arguments"))),
+    `Executes the named program with the given arguments. Returns a map with the following keys:
+      :success - whether or not the execution was successful,
+      :out - string capturing stdout of the program,
+      :err - string capturing stderr of the program.`, "1.0"))
+
+osNamespace.InternVar("env", env_,
+  MakeMeta(
+    NewListFrom(NewVectorFrom()),
+    `Returns a map representing the environment.`, "1.0"))
+
+osNamespace.InternVar("args", args_,
+  MakeMeta(
+    NewListFrom(NewVectorFrom()),
+    `Returns a sequence of the command line arguments, starting with the program name (normally, joker).`, "1.0"))
+
+osNamespace.InternVar("exit", exit_,
+  MakeMeta(
+    NewListFrom(NewVectorFrom(MakeSymbol("code"))),
+    `Causes the current program to exit with the given status code.`, "1.0"))
+
+}
diff --git a/std/string/a_string.go b/std/string/a_string.go
new file mode 100644
index 000000000..58311fb6c
--- /dev/null
+++ b/std/string/a_string.go
@@ -0,0 +1,521 @@
+// This file is generated by generate-std.joke script. Do not edit manually!
+
+package string
+
+import (
+  "strings"
+  "unicode"
+  . "github.com/candid82/joker/core"
+)
+
+var stringNamespace = GLOBAL_ENV.EnsureNamespace(MakeSymbol("joker.string"))
+
+var index_of_ Proc = func(args []Object) Object {
+  c := len(args)
+  switch  {
+  case c == 2:
+    
+    s := ExtractString(args, 0)
+    value := ExtractObject(args, 1)
+    res := indexOf(s, value, 0)
+    return res
+
+  case c == 3:
+    
+    s := ExtractString(args, 0)
+    value := ExtractObject(args, 1)
+    from := ExtractInt(args, 2)
+    res := indexOf(s, value, from)
+    return res
+
+  default:
+    PanicArity(c)
+  }
+  return NIL
+}
+
+var lower_case_ Proc = func(args []Object) Object {
+  c := len(args)
+  switch  {
+  case c == 1:
+    
+    s := ExtractString(args, 0)
+    res := strings.ToLower(s)
+    return MakeString(res)
+
+  default:
+    PanicArity(c)
+  }
+  return NIL
+}
+
+var reverse_ Proc = func(args []Object) Object {
+  c := len(args)
+  switch  {
+  case c == 1:
+    
+    s := ExtractString(args, 0)
+    res := reverse(s)
+    return MakeString(res)
+
+  default:
+    PanicArity(c)
+  }
+  return NIL
+}
+
+var split_ Proc = func(args []Object) Object {
+  c := len(args)
+  switch  {
+  case c == 2:
+    
+    s := ExtractString(args, 0)
+    re := ExtractRegex(args, 1)
+    res := split(s, re, 0)
+    return res
+
+  case c == 3:
+    
+    s := ExtractString(args, 0)
+    re := ExtractRegex(args, 1)
+    n := ExtractInt(args, 2)
+    res := split(s, re, n)
+    return res
+
+  default:
+    PanicArity(c)
+  }
+  return NIL
+}
+
+var isstarts_with_ Proc = func(args []Object) Object {
+  c := len(args)
+  switch  {
+  case c == 2:
+    
+    s := ExtractString(args, 0)
+    substr := ExtractString(args, 1)
+    res := strings.HasPrefix(s, substr)
+    return MakeBool(res)
+
+  default:
+    PanicArity(c)
+  }
+  return NIL
+}
+
+var trim_left_ Proc = func(args []Object) Object {
+  c := len(args)
+  switch  {
+  case c == 1:
+    
+    s := ExtractString(args, 0)
+    res := strings.TrimLeftFunc(s, unicode.IsSpace)
+    return MakeString(res)
+
+  default:
+    PanicArity(c)
+  }
+  return NIL
+}
+
+var isends_with_ Proc = func(args []Object) Object {
+  c := len(args)
+  switch  {
+  case c == 2:
+    
+    s := ExtractString(args, 0)
+    substr := ExtractString(args, 1)
+    res := strings.HasSuffix(s, substr)
+    return MakeBool(res)
+
+  default:
+    PanicArity(c)
+  }
+  return NIL
+}
+
+var trim_ Proc = func(args []Object) Object {
+  c := len(args)
+  switch  {
+  case c == 1:
+    
+    s := ExtractString(args, 0)
+    res := strings.TrimSpace(s)
+    return MakeString(res)
+
+  default:
+    PanicArity(c)
+  }
+  return NIL
+}
+
+var escape_ Proc = func(args []Object) Object {
+  c := len(args)
+  switch  {
+  case c == 2:
+    
+    s := ExtractString(args, 0)
+    cmap := ExtractCallable(args, 1)
+    res := escape(s, cmap)
+    return MakeString(res)
+
+  default:
+    PanicArity(c)
+  }
+  return NIL
+}
+
+var join_ Proc = func(args []Object) Object {
+  c := len(args)
+  switch  {
+  case c == 1:
+    
+    coll := ExtractSeqable(args, 0)
+    res := join("", coll)
+    return MakeString(res)
+
+  case c == 2:
+    
+    separator := ExtractString(args, 0)
+    coll := ExtractSeqable(args, 1)
+    res := join(separator, coll)
+    return MakeString(res)
+
+  default:
+    PanicArity(c)
+  }
+  return NIL
+}
+
+var pad_right_ Proc = func(args []Object) Object {
+  c := len(args)
+  switch  {
+  case c == 3:
+    
+    s := ExtractString(args, 0)
+    pad := ExtractString(args, 1)
+    n := ExtractInt(args, 2)
+    res := padRight(s, pad, n)
+    return MakeString(res)
+
+  default:
+    PanicArity(c)
+  }
+  return NIL
+}
+
+var capitalize_ Proc = func(args []Object) Object {
+  c := len(args)
+  switch  {
+  case c == 1:
+    
+    s := ExtractString(args, 0)
+    res := capitalize(s)
+    return MakeString(res)
+
+  default:
+    PanicArity(c)
+  }
+  return NIL
+}
+
+var replace_first_ Proc = func(args []Object) Object {
+  c := len(args)
+  switch  {
+  case c == 3:
+    
+    s := ExtractString(args, 0)
+    match := ExtractObject(args, 1)
+    repl := ExtractString(args, 2)
+    res := replaceFirst(s, match, repl)
+    return MakeString(res)
+
+  default:
+    PanicArity(c)
+  }
+  return NIL
+}
+
+var pad_left_ Proc = func(args []Object) Object {
+  c := len(args)
+  switch  {
+  case c == 3:
+    
+    s := ExtractString(args, 0)
+    pad := ExtractString(args, 1)
+    n := ExtractInt(args, 2)
+    res := padLeft(s, pad, n)
+    return MakeString(res)
+
+  default:
+    PanicArity(c)
+  }
+  return NIL
+}
+
+var isblank_ Proc = func(args []Object) Object {
+  c := len(args)
+  switch  {
+  case c == 1:
+    
+    s := ExtractObject(args, 0)
+    res := isBlank(s)
+    return MakeBool(res)
+
+  default:
+    PanicArity(c)
+  }
+  return NIL
+}
+
+var upper_case_ Proc = func(args []Object) Object {
+  c := len(args)
+  switch  {
+  case c == 1:
+    
+    s := ExtractString(args, 0)
+    res := strings.ToUpper(s)
+    return MakeString(res)
+
+  default:
+    PanicArity(c)
+  }
+  return NIL
+}
+
+var isincludes_ Proc = func(args []Object) Object {
+  c := len(args)
+  switch  {
+  case c == 2:
+    
+    s := ExtractString(args, 0)
+    substr := ExtractString(args, 1)
+    res := strings.Contains(s, substr)
+    return MakeBool(res)
+
+  default:
+    PanicArity(c)
+  }
+  return NIL
+}
+
+var last_index_of_ Proc = func(args []Object) Object {
+  c := len(args)
+  switch  {
+  case c == 2:
+    
+    s := ExtractString(args, 0)
+    value := ExtractObject(args, 1)
+    res := lastIndexOf(s, value, 0)
+    return res
+
+  case c == 3:
+    
+    s := ExtractString(args, 0)
+    value := ExtractObject(args, 1)
+    from := ExtractInt(args, 2)
+    res := lastIndexOf(s, value, from)
+    return res
+
+  default:
+    PanicArity(c)
+  }
+  return NIL
+}
+
+var trim_newline_ Proc = func(args []Object) Object {
+  c := len(args)
+  switch  {
+  case c == 1:
+    
+    s := ExtractString(args, 0)
+    res := strings.TrimRight(s, "\n\r")
+    return MakeString(res)
+
+  default:
+    PanicArity(c)
+  }
+  return NIL
+}
+
+var split_lines_ Proc = func(args []Object) Object {
+  c := len(args)
+  switch  {
+  case c == 1:
+    
+    s := ExtractString(args, 0)
+    res := split(s, newLine, 0)
+    return res
+
+  default:
+    PanicArity(c)
+  }
+  return NIL
+}
+
+var trim_right_ Proc = func(args []Object) Object {
+  c := len(args)
+  switch  {
+  case c == 1:
+    
+    s := ExtractString(args, 0)
+    res := strings.TrimRightFunc(s, unicode.IsSpace)
+    return MakeString(res)
+
+  default:
+    PanicArity(c)
+  }
+  return NIL
+}
+
+var replace_ Proc = func(args []Object) Object {
+  c := len(args)
+  switch  {
+  case c == 3:
+    
+    s := ExtractString(args, 0)
+    match := ExtractObject(args, 1)
+    repl := ExtractString(args, 2)
+    res := replace(s, match, repl)
+    return MakeString(res)
+
+  default:
+    PanicArity(c)
+  }
+  return NIL
+}
+
+
+func init() {
+
+stringNamespace.ResetMeta(MakeMeta(nil, "Implements simple functions to manipulate strings.", "1.0"))
+
+stringNamespace.InternVar("index-of", index_of_,
+  MakeMeta(
+    NewListFrom(NewVectorFrom(MakeSymbol("s"), MakeSymbol("value")), NewVectorFrom(MakeSymbol("s"), MakeSymbol("value"), MakeSymbol("from"))),
+    `Return index of value (string or char) in s, optionally searching
+  forward from from or nil if not found.`, "1.0"))
+
+stringNamespace.InternVar("lower-case", lower_case_,
+  MakeMeta(
+    NewListFrom(NewVectorFrom(MakeSymbol("s"))),
+    `Converts string to all lower-case.`, "1.0"))
+
+stringNamespace.InternVar("reverse", reverse_,
+  MakeMeta(
+    NewListFrom(NewVectorFrom(MakeSymbol("s"))),
+    `Returns s with its characters reversed.`, "1.0"))
+
+stringNamespace.InternVar("split", split_,
+  MakeMeta(
+    NewListFrom(NewVectorFrom(MakeSymbol("s"), MakeSymbol("re")), NewVectorFrom(MakeSymbol("s"), MakeSymbol("re"), MakeSymbol("n"))),
+    `Splits string on a regular expression. Returns vector of the splits.`, "1.0"))
+
+stringNamespace.InternVar("starts-with?", isstarts_with_,
+  MakeMeta(
+    NewListFrom(NewVectorFrom(MakeSymbol("s"), MakeSymbol("substr"))),
+    `True if s starts with substr.`, "1.0"))
+
+stringNamespace.InternVar("trim-left", trim_left_,
+  MakeMeta(
+    NewListFrom(NewVectorFrom(MakeSymbol("s"))),
+    `Removes whitespace from the left side of string.`, "1.0"))
+
+stringNamespace.InternVar("ends-with?", isends_with_,
+  MakeMeta(
+    NewListFrom(NewVectorFrom(MakeSymbol("s"), MakeSymbol("substr"))),
+    `True if s ends with substr.`, "1.0"))
+
+stringNamespace.InternVar("trim", trim_,
+  MakeMeta(
+    NewListFrom(NewVectorFrom(MakeSymbol("s"))),
+    `Removes whitespace from both ends of string.`, "1.0"))
+
+stringNamespace.InternVar("escape", escape_,
+  MakeMeta(
+    NewListFrom(NewVectorFrom(MakeSymbol("s"), MakeSymbol("cmap"))),
+    `Return a new string, using cmap to escape each character ch
+  from s as follows:
+
+  If (cmap ch) is nil, append ch to the new string.
+  If (cmap ch) is non-nil, append (str (cmap ch)) instead.`, "1.0"))
+
+stringNamespace.InternVar("join", join_,
+  MakeMeta(
+    NewListFrom(NewVectorFrom(MakeSymbol("coll")), NewVectorFrom(MakeSymbol("separator"), MakeSymbol("coll"))),
+    `Returns a string of all elements in coll, as returned by (seq coll), separated by an optional separator.`, "1.0"))
+
+stringNamespace.InternVar("pad-right", pad_right_,
+  MakeMeta(
+    NewListFrom(NewVectorFrom(MakeSymbol("s"), MakeSymbol("pad"), MakeSymbol("n"))),
+    `Returns s padded with pad at the end to length n.`, "1.0"))
+
+stringNamespace.InternVar("capitalize", capitalize_,
+  MakeMeta(
+    NewListFrom(NewVectorFrom(MakeSymbol("s"))),
+    `Converts first character of the string to upper-case, all other
+  characters to lower-case.`, "1.0"))
+
+stringNamespace.InternVar("replace-first", replace_first_,
+  MakeMeta(
+    NewListFrom(NewVectorFrom(MakeSymbol("s"), MakeSymbol("match"), MakeSymbol("repl"))),
+    `Replaces the first instance of match (String of Regex) with string repl in string s.
+
+  If match is Regex, $1, $2, etc. in the replacement string repl are
+  substituted with the string that matched the corresponding
+  parenthesized group in the pattern.
+  `, "1.0"))
+
+stringNamespace.InternVar("pad-left", pad_left_,
+  MakeMeta(
+    NewListFrom(NewVectorFrom(MakeSymbol("s"), MakeSymbol("pad"), MakeSymbol("n"))),
+    `Returns s padded with pad at the beginning to length n.`, "1.0"))
+
+stringNamespace.InternVar("blank?", isblank_,
+  MakeMeta(
+    NewListFrom(NewVectorFrom(MakeSymbol("s"))),
+    `True if s is nil, empty, or contains only whitespace.`, "1.0"))
+
+stringNamespace.InternVar("upper-case", upper_case_,
+  MakeMeta(
+    NewListFrom(NewVectorFrom(MakeSymbol("s"))),
+    `Converts string to all upper-case.`, "1.0"))
+
+stringNamespace.InternVar("includes?", isincludes_,
+  MakeMeta(
+    NewListFrom(NewVectorFrom(MakeSymbol("s"), MakeSymbol("substr"))),
+    `True if s includes substr.`, "1.0"))
+
+stringNamespace.InternVar("last-index-of", last_index_of_,
+  MakeMeta(
+    NewListFrom(NewVectorFrom(MakeSymbol("s"), MakeSymbol("value")), NewVectorFrom(MakeSymbol("s"), MakeSymbol("value"), MakeSymbol("from"))),
+    `Return last index of value (string or char) in s, optionally
+  searching backward from from or nil if not found.`, "1.0"))
+
+stringNamespace.InternVar("trim-newline", trim_newline_,
+  MakeMeta(
+    NewListFrom(NewVectorFrom(MakeSymbol("s"))),
+    `Removes all trailing newline \n or return \r characters from string.`, "1.0"))
+
+stringNamespace.InternVar("split-lines", split_lines_,
+  MakeMeta(
+    NewListFrom(NewVectorFrom(MakeSymbol("s"))),
+    `Splits string on \n or \r\n. Returns vector of the splits.`, "1.0"))
+
+stringNamespace.InternVar("trim-right", trim_right_,
+  MakeMeta(
+    NewListFrom(NewVectorFrom(MakeSymbol("s"))),
+    `Removes whitespace from the right side of string.`, "1.0"))
+
+stringNamespace.InternVar("replace", replace_,
+  MakeMeta(
+    NewListFrom(NewVectorFrom(MakeSymbol("s"), MakeSymbol("match"), MakeSymbol("repl"))),
+    `Replaces all instances of match (String of Regex) with string repl in string s.
+
+  If match is Regex, $1, $2, etc. in the replacement string repl are
+  substituted with the string that matched the corresponding
+  parenthesized group in the pattern.
+  `, "1.0"))
+
+}
diff --git a/std/time/a_time.go b/std/time/a_time.go
new file mode 100644
index 000000000..5f538bf85
--- /dev/null
+++ b/std/time/a_time.go
@@ -0,0 +1,38 @@
+// This file is generated by generate-std.joke script. Do not edit manually!
+
+package time
+
+import (
+  
+  . "github.com/candid82/joker/core"
+)
+
+var timeNamespace = GLOBAL_ENV.EnsureNamespace(MakeSymbol("joker.time"))
+
+var sleep_ Proc = func(args []Object) Object {
+  c := len(args)
+  switch  {
+  case c == 1:
+    
+    d := ExtractInt(args, 0)
+    res := sleep(d)
+    return res
+
+  default:
+    PanicArity(c)
+  }
+  return NIL
+}
+
+
+func init() {
+
+timeNamespace.ResetMeta(MakeMeta(nil, "Provides functionality for measuring and displaying time.", "1.0"))
+
+timeNamespace.InternVar("sleep", sleep_,
+  MakeMeta(
+    NewListFrom(NewVectorFrom(MakeSymbol("d"))),
+    `Pauses the execution thread for at least the duration d (expressed in nanoseconds).
+  A negative or zero duration causes sleep to return immediately.`, "1.0"))
+
+}