# This file is part of NIT ( http://www.nitlanguage.org ).
#
# Copyright 2014 Alexis Laferrière <alexis.laf@xymus.net>
+# Copyright 2014 Alexandre Terrasa <alexandre@moz-concept.com>
+# Copyright 2014 Jean-Christophe Beaupré <jcbrinfo@users.noreply.github.com>
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# Static interface to get Nit objects from a Json string.
#
-# `String::json_to_nit_object` returns an equivalent Nit object from
+# `Text::parse_json` returns an equivalent Nit object from
# the Json source. This object can then be type checked by the usual
# languages features (`isa` and `as`).
module static
+import error
private import json_parser
private import json_lexer
+# Something that can be translated to JSON.
+interface Jsonable
+ # Encode `self` in JSON.
+ #
+ # SEE: `append_json`
+ fun to_json: String is abstract
+
+ # Use `append_json` to implement `to_json`.
+ #
+ # Therefore, one that redefine `append_json` may use the following
+ # redefinition to link `to_json` and `append_json`:
+ #
+ # ~~~nitish
+ # redef fun to_json do return to_json_by_append
+ # ~~~
+ #
+ # Note: This is not the default implementation of `to_json` in order to
+ # avoid cyclic references between `append_json` and `to_json` when none are
+ # implemented.
+ protected fun to_json_by_append: String do
+ var buffer = new RopeBuffer
+ append_json(buffer)
+ return buffer.write_to_string
+ end
+
+ # Append the JSON representation of `self` to the specified buffer.
+ #
+ # SEE: `to_json`
+ fun append_json(buffer: Buffer) do buffer.append(to_json)
+
+ # Pretty print JSON string.
+ #
+ # ~~~
+ # var obj = new JsonObject
+ # obj["foo"] = 1
+ # obj["bar"] = true
+ # var arr = new JsonArray
+ # arr.add 2
+ # arr.add false
+ # arr.add "baz"
+ # obj["baz"] = arr
+ # var res = obj.to_pretty_json
+ # var exp = """{
+ # \t"foo": 1,
+ # \t"bar": true,
+ # \t"baz": [2, false, "baz"]
+ # }\n"""
+ # assert res == exp
+ # ~~~
+ fun to_pretty_json: String do
+ var res = new FlatBuffer
+ pretty_json_visit(res, 0)
+ res.add '\n'
+ return res.write_to_string
+ end
+
+ private fun pretty_json_visit(buffer: FlatBuffer, indent: Int) is abstract
+end
+
+redef class Text
+ super Jsonable
+
+ redef fun append_json(buffer) do
+ buffer.add '\"'
+ for i in [0..self.length[ do
+ var char = self[i]
+ if char == '\\' then
+ buffer.append "\\\\"
+ else if char == '\"' then
+ buffer.append "\\\""
+ else if char == '\/' then
+ buffer.append "\\/"
+ else if char < 16.code_point then
+ if char == '\n' then
+ buffer.append "\\n"
+ else if char == '\r' then
+ buffer.append "\\r"
+ else if char == '\t' then
+ buffer.append "\\t"
+ else if char == 0x0C.code_point then
+ buffer.append "\\f"
+ else if char == 0x08.code_point then
+ buffer.append "\\b"
+ else
+ buffer.append "\\u000{char.code_point.to_hex}"
+ end
+ else if char < ' ' then
+ buffer.append "\\u00{char.code_point.to_hex}"
+ else
+ buffer.add char
+ end
+ end
+ buffer.add '\"'
+ end
+
+ # Encode `self` in JSON.
+ #
+ # ~~~
+ # assert "\t\"http://example.com\"\r\n\0\\".to_json ==
+ # "\"\\t\\\"http:\\/\\/example.com\\\"\\r\\n\\u0000\\\\\""
+ # ~~~
+ redef fun to_json do return to_json_by_append
+
+ # Parse `self` as JSON.
+ #
+ # If `self` is not a valid JSON document or contains an unsupported escape
+ # sequence, return a `JSONParseError`.
+ #
+ # Example with `JsonObject`:
+ #
+ # var obj = "\{\"foo\": \{\"bar\": true, \"goo\": [1, 2, 3]\}\}".parse_json
+ # assert obj isa JsonObject
+ # assert obj["foo"] isa JsonObject
+ # assert obj["foo"].as(JsonObject)["bar"] == true
+ #
+ # Example with `JsonArray`:
+ #
+ # var arr = "[1, 2, 3]".parse_json
+ # assert arr isa JsonArray
+ # assert arr.length == 3
+ # assert arr.first == 1
+ # assert arr.last == 3
+ #
+ # Example with `String`:
+ #
+ # var str = "\"foo, bar, baz\"".parse_json
+ # assert str isa String
+ # assert str == "foo, bar, baz"
+ #
+ # Example of a syntaxic error:
+ #
+ # var bad = "\{foo: \"bar\"\}".parse_json
+ # assert bad isa JsonParseError
+ # assert bad.position.col_start == 2
+ fun parse_json: nullable Jsonable do
+ var lexer = new Lexer_json(to_s)
+ var parser = new Parser_json
+ var tokens = lexer.lex
+ parser.tokens.add_all(tokens)
+ var root_node = parser.parse
+ if root_node isa NStart then
+ return root_node.n_0.to_nit_object
+ else if root_node isa NError then
+ return new JsonParseError(root_node.message, root_node.position)
+ else abort
+ end
+end
+
+redef class Buffer
+
+ # Append the JSON representation of `jsonable` to `self`.
+ #
+ # Append `"null"` for `null`.
+ private fun append_json_of(jsonable: nullable Jsonable) do
+ if jsonable isa Jsonable then
+ append jsonable.to_json
+ else
+ append "null"
+ end
+ end
+end
+
+redef class Int
+ super Jsonable
+
+ # Encode `self` in JSON.
+ #
+ # assert 0.to_json == "0"
+ # assert (-42).to_json == "-42"
+ redef fun to_json do return self.to_s
+end
+
+redef class Float
+ super Jsonable
+
+ # Encode `self` in JSON.
+ #
+ # Note: Because this method use `to_s`, it may lose precision.
+ #
+ # ~~~
+ # # Will not work as expected.
+ # # assert (-0.0).to_json == "-0.0"
+ #
+ # assert (.5).to_json == "0.5"
+ # assert (0.0).to_json == "0.0"
+ # ~~~
+ redef fun to_json do return self.to_s
+end
+
+redef class Bool
+ super Jsonable
+
+ # Encode `self` in JSON.
+ #
+ # assert true.to_json == "true"
+ # assert false.to_json == "false"
+ redef fun to_json do return self.to_s
+end
+
+# A map that can be translated into a JSON object.
+interface JsonMapRead[K: String, V: nullable Jsonable]
+ super MapRead[K, V]
+ super Jsonable
+
+ redef fun append_json(buffer) do
+ buffer.append "\{"
+ var it = iterator
+ if it.is_ok then
+ append_json_entry(it, buffer)
+ while it.is_ok do
+ buffer.append ","
+ append_json_entry(it, buffer)
+ end
+ end
+ it.finish
+ buffer.append "\}"
+ end
+
+ # Encode `self` in JSON.
+ #
+ # var obj = new JsonObject
+ # obj["foo"] = "bar"
+ # assert obj.to_json == "\{\"foo\":\"bar\"\}"
+ # obj = new JsonObject
+ # obj["baz"] = null
+ # assert obj.to_json == "\{\"baz\":null\}"
+ redef fun to_json do return to_json_by_append
+
+ redef fun pretty_json_visit(buffer, indent) do
+ buffer.append "\{\n"
+ indent += 1
+ var i = 0
+ for k, v in self do
+ buffer.append "\t" * indent
+ buffer.append "\"{k}\": "
+ if v isa JsonObject or v isa JsonArray then
+ v.pretty_json_visit(buffer, indent)
+ else
+ buffer.append v.to_json
+ end
+ if i < length - 1 then
+ buffer.append ","
+ end
+ buffer.append "\n"
+ i += 1
+ end
+ indent -= 1
+ buffer.append "\t" * indent
+ buffer.append "\}"
+ end
+
+ private fun append_json_entry(iterator: MapIterator[String, nullable Jsonable],
+ buffer: Buffer) do
+ buffer.append iterator.key.to_json
+ buffer.append ":"
+ buffer.append_json_of(iterator.item)
+ iterator.next
+ end
+end
+
+# A JSON Object.
+class JsonObject
+ super JsonMapRead[String, nullable Jsonable]
+ super HashMap[String, nullable Jsonable]
+end
+
+# A sequence that can be translated into a JSON array.
+class JsonSequenceRead[E: nullable Jsonable]
+ super Jsonable
+ super SequenceRead[E]
+
+ redef fun append_json(buffer) do
+ buffer.append "["
+ var it = iterator
+ if it.is_ok then
+ append_json_entry(it, buffer)
+ while it.is_ok do
+ buffer.append ","
+ append_json_entry(it, buffer)
+ end
+ end
+ it.finish
+ buffer.append "]"
+ end
+
+ # Encode `self` in JSON.
+ #
+ # var arr = new JsonArray.with_items("foo", null)
+ # assert arr.to_json == "[\"foo\",null]"
+ # arr.pop
+ # assert arr.to_json =="[\"foo\"]"
+ # arr.pop
+ # assert arr.to_json =="[]"
+ redef fun to_json do return to_json_by_append
+
+ redef fun pretty_json_visit(buffer, indent) do
+ buffer.append "\["
+ var i = 0
+ for v in self do
+ if v isa JsonObject or v isa JsonArray then
+ v.pretty_json_visit(buffer, indent)
+ else
+ buffer.append v.to_json
+ end
+ if i < length - 1 then buffer.append ", "
+ i += 1
+ end
+ buffer.append "\]"
+ end
+
+ private fun append_json_entry(iterator: Iterator[nullable Jsonable],
+ buffer: Buffer) do
+ buffer.append_json_of(iterator.item)
+ iterator.next
+ end
+end
+
+# A JSON array.
+class JsonArray
+ super JsonSequenceRead[nullable Jsonable]
+ super Array[nullable Jsonable]
+end
+
+redef class JsonParseError
+ super Jsonable
+
+ # Get the JSON representation of `self`.
+ #
+ # ~~~
+ # var err = new JsonParseError("foo", new Position(1, 2, 3, 4, 5, 6))
+ # assert err.to_json == "\{\"error\":\"JsonParseError\"," +
+ # "\"position\":\{" +
+ # "\"pos_start\":1,\"pos_end\":2," +
+ # "\"line_start\":3,\"line_end\":4," +
+ # "\"col_start\":5,\"col_end\":6" +
+ # "\},\"message\":\"foo\"\}"
+ # ~~~
+ redef fun to_json do
+ return "\{\"error\":\"JsonParseError\"," +
+ "\"position\":{position.to_json}," +
+ "\"message\":{message.to_json}\}"
+ end
+end
+
+redef class Position
+ super Jsonable
+
+ # Get the JSON representation of `self`.
+ #
+ # ~~~
+ # var pos = new Position(1, 2, 3, 4, 5, 6)
+ # assert pos.to_json == "\{" +
+ # "\"pos_start\":1,\"pos_end\":2," +
+ # "\"line_start\":3,\"line_end\":4," +
+ # "\"col_start\":5,\"col_end\":6" +
+ # "\}"
+ # ~~~
+ redef fun to_json do
+ return "\{\"pos_start\":{pos_start},\"pos_end\":{pos_end}," +
+ "\"line_start\":{line_start},\"line_end\":{line_end}," +
+ "\"col_start\":{col_start},\"col_end\":{col_end}\}"
+ end
+end
+
+################################################################################
+# Redef parser
+
redef class Nvalue
- fun to_nit_object: nullable Object is abstract
+ # The represented value.
+ private fun to_nit_object: nullable Jsonable is abstract
end
redef class Nvalue_number
end
redef class Nstring
- # FIXME support \n, etc.
- fun to_nit_string: String do return text.substring(1, text.length-2).
- replace("\\\\", "\\").replace("\\\"", "\"").replace("\\b", "\b").
- replace("\\/", "/").replace("\\n", "\n").replace("\\r", "\r").
- replace("\\t", "\t")
+ # The represented string.
+ private fun to_nit_string: String do
+ var res = new FlatBuffer
+ var i = 1
+ while i < text.length - 1 do
+ var char = text[i]
+ if char == '\\' then
+ i += 1
+ char = text[i]
+ if char == 'b' then
+ char = 0x08.code_point
+ else if char == 'f' then
+ char = 0x0C.code_point
+ else if char == 'n' then
+ char = '\n'
+ else if char == 'r' then
+ char = '\r'
+ else if char == 't' then
+ char = '\t'
+ else if char == 'u' then
+ var code = text.substring(i + 1, 4).to_hex
+ # TODO UTF-16 escaping is not supported yet.
+ if code >= 128 then
+ char = '?'
+ else
+ char = code.code_point
+ end
+ i += 4
+ end
+ # `"`, `/` or `\` => Keep `char` as-is.
+ end
+ res.add char
+ i += 1
+ end
+ return res.write_to_string
+ end
end
redef class Nvalue_object
- redef fun to_nit_object
- do
- var obj = new HashMap[String, nullable Object]
+ redef fun to_nit_object do
+ var obj = new JsonObject
var members = n_members
if members != null then
var pairs = members.pairs
end
redef class Nmembers
- fun pairs: Array[Npair] is abstract
+ # All the key-value pairs.
+ private fun pairs: Array[Npair] is abstract
end
redef class Nmembers_tail
end
redef class Npair
- fun name: String do return n_string.to_nit_string
- fun value: nullable Object do return n_value.to_nit_object
+ # The represented key.
+ private fun name: String do return n_string.to_nit_string
+
+ # The represented value.
+ private fun value: nullable Jsonable do return n_value.to_nit_object
end
redef class Nvalue_array
redef fun to_nit_object
do
- var arr = new Array[nullable Object]
+ var arr = new JsonArray
var elements = n_elements
if elements != null then
var items = elements.items
end
redef class Nelements
- fun items: Array[Nvalue] is abstract
+ # All the items.
+ private fun items: Array[Nvalue] is abstract
end
redef class Nelements_tail
redef class Nelements_head
redef fun items do return [n_value]
end
-
-redef class String
- fun json_to_nit_object: nullable Object
- do
- var lexer = new Lexer_json(self)
- var parser = new Parser_json
- var tokens = lexer.lex
- parser.tokens.add_all(tokens)
- var root_node = parser.parse
- if root_node isa NStart then
- return root_node.n_0.to_nit_object
- else if root_node isa NLexerError then
- var pos = root_node.position
- print "Json lexer error: {root_node.message} at {pos or else "<unknown>"} for {root_node}"
- return null
- else if root_node isa NParserError then
- var pos = root_node.position
- print "Json parsing error: {root_node.message} at {pos or else "<unknown>"} for {root_node}"
- return null
- else abort
- end
-end
nitlanguage / nit.git / blobdiff