bjoernager/rust
bjoernager/rust
1
Fork 0
Code Activity

Establish 'core' library separate from 'std'.

Browse source
This commit is contained in:
Graydon Hoare 2011-12-05 16:46:37 -08:00
parent b513a5a500
commit 447414f007
76 changed files with 114 additions and 30 deletions
Download patch file Download diff file Expand all files Collapse all files

258
src/libstd/json.rs Normal file
View file

@ -0,0 +1,258 @@
// Rust JSON serialization library
// Copyright (c) 2011 Google Inc.
import float;
import map;
import option;
import option::{some, none};
import str;
import vec;
export json;
export to_str;
export from_str;
export num;
export string;
export boolean;
export list;
export dict;
/*
Tag: json
Represents a json value.
*/
tag json {
/* Variant: num */
num(float);
/* Variant: string */
string(str);
/* Variant: boolean */
boolean(bool);
/* Variant: list */
list(@[json]);
/* Variant: dict */
dict(map::hashmap<str,json>);
}
/*
Function: to_str
Serializes a json value into a string.
*/
fn to_str(j: json) -> str {
alt j {
num(f) { float::to_str(f, 6u) }
string(s) { #fmt["\"%s\"", s] } // XXX: escape
boolean(true) { "true" }
boolean(false) { "false" }
list(@js) {
str::concat(["[",
str::connect(
vec::map::<json,str>({ |e| to_str(e) }, js),
", "),
"]"])
}
dict(m) {
let parts = [];
m.items({ |k, v|
vec::grow(parts, 1u,
str::concat(["\"", k, "\": ", to_str(v)])
)
});
str::concat(["{ ", str::connect(parts, ", "), " }"])
}
}
}
fn rest(s: str) -> str {
assert(str::char_len(s) >= 1u);
str::char_slice(s, 1u, str::char_len(s))
}
fn from_str_str(s: str) -> (option::t<json>, str) {
let pos = 0u;
let len = str::byte_len(s);
let escape = false;
let res = "";
alt str::char_at(s, 0u) {
'"' { pos = 1u; }
_ { ret (none, s); }
}
while (pos < len) {
let chr = str::char_range_at(s, pos);
let c = chr.ch;
pos = chr.next;
if (escape) {
res = res + str::from_char(c);
escape = false;
cont;
}
if (c == '\\') {
escape = true;
cont;
} else if (c == '"') {
ret (some(string(res)),
str::char_slice(s, pos, str::char_len(s)));
}
res = res + str::from_char(c);
}
ret (none, s);
}
fn from_str_list(s: str) -> (option::t<json>, str) {
if str::char_at(s, 0u) != '[' { ret (none, s); }
let s0 = str::trim_left(rest(s));
let vals = [];
if str::is_empty(s0) { ret (none, s0); }
if str::char_at(s0, 0u) == ']' { ret (some(list(@[])), rest(s0)); }
while str::is_not_empty(s0) {
s0 = str::trim_left(s0);
let (next, s1) = from_str_helper(s0);
s0 = s1;
alt next {
some(j) { vec::grow(vals, 1u, j); }
none { ret (none, s0); }
}
s0 = str::trim_left(s0);
if str::is_empty(s0) { ret (none, s0); }
alt str::char_at(s0, 0u) {
',' { }
']' { ret (some(list(@vals)), rest(s0)); }
_ { ret (none, s0); }
}
s0 = rest(s0);
}
ret (none, s0);
}
fn from_str_dict(s: str) -> (option::t<json>, str) {
if str::char_at(s, 0u) != '{' { ret (none, s); }
let s0 = str::trim_left(rest(s));
let vals = map::new_str_hash::<json>();
if str::is_empty(s0) { ret (none, s0); }
if str::char_at(s0, 0u) == '}' { ret (some(dict(vals)), rest(s0)); }
while str::is_not_empty(s0) {
s0 = str::trim_left(s0);
let (next, s1) = from_str_helper(s0); // key
let key = "";
s0 = s1;
alt next {
some(string(k)) { key = k; }
_ { ret (none, s0); }
}
s0 = str::trim_left(s0);
if str::is_empty(s0) { ret (none, s0); }
if str::char_at(s0, 0u) != ':' { ret (none, s0); }
s0 = str::trim_left(rest(s0));
let (next, s1) = from_str_helper(s0); // value
s0 = s1;
alt next {
some(j) { vals.insert(key, j); }
_ { ret (none, s0); }
}
s0 = str::trim_left(s0);
if str::is_empty(s0) { ret (none, s0); }
alt str::char_at(s0, 0u) {
',' { }
'}' { ret (some(dict(vals)), rest(s0)); }
_ { ret (none, s0); }
}
s0 = str::trim_left(rest(s0));
}
(none, s)
}
fn from_str_float(s: str) -> (option::t<json>, str) {
let pos = 0u;
let len = str::byte_len(s);
let res = 0f;
let neg = 1.f;
alt str::char_at(s, 0u) {
'-' {
neg = -1.f;
pos = 1u;
}
'+' {
pos = 1u;
}
'0' to '9' | '.' { }
_ { ret (none, s); }
}
while (pos < len) {
let opos = pos;
let chr = str::char_range_at(s, pos);
let c = chr.ch;
pos = chr.next;
alt c {
'0' to '9' {
res = res * 10f;
res += ((c as int) - ('0' as int)) as float;
}
'.' { break; }
_ { ret (some(num(neg * res)),
str::char_slice(s, opos, str::char_len(s))); }
}
}
if pos == len {
ret (some(num(neg * res)), str::char_slice(s, pos, str::char_len(s)));
}
let dec = 1.f;
while (pos < len) {
let opos = pos;
let chr = str::char_range_at(s, pos);
let c = chr.ch;
pos = chr.next;
alt c {
'0' to '9' {
dec /= 10.f;
res += (((c as int) - ('0' as int)) as float) * dec;
}
_ { ret (some(num(neg * res)),
str::char_slice(s, opos, str::char_len(s))); }
}
}
ret (some(num(neg * res)), str::char_slice(s, pos, str::char_len(s)));
}
fn from_str_bool(s: str) -> (option::t<json>, str) {
if (str::starts_with(s, "true")) {
(some(boolean(true)), str::slice(s, 4u, str::byte_len(s)))
} else if (str::starts_with(s, "false")) {
(some(boolean(false)), str::slice(s, 5u, str::byte_len(s)))
} else {
(none, s)
}
}
fn from_str_helper(s: str) -> (option::t<json>, str) {
let s = str::trim_left(s);
if str::is_empty(s) { ret (none, s); }
let start = str::char_at(s, 0u);
alt start {
'"' { from_str_str(s) }
'[' { from_str_list(s) }
'{' { from_str_dict(s) }
'0' to '9' | '-' | '+' | '.' { from_str_float(s) }
't' | 'f' { from_str_bool(s) }
_ { ret (none, s); }
}
}
/*
Function: from_str
Deserializes a json value from a string.
*/
fn from_str(s: str) -> option::t<json> {
let (j, _) = from_str_helper(s);
j
}