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#[doc="Constructs a list of css style rules from a token stream"]
// TODO: fail according to the css spec instead of failing when things
// are not as expected
import dom::style;
import style::{DisInline, DisBlock, DisNone, Display, TextColor, BackgroundColor, FontSize,
Height, Width, StyleDeclaration, Selector};
import parser::css_lexer::{Token, StartDescription, EndDescription,
Descendant, Child, Sibling,
Comma, Element, Attr, Description,
Eof};
import comm::recv;
import option::{map, is_none};
import vec::push;
import parser::parser_util::{parse_display_type, parse_font_size, parse_size};
import util::color::parsing::parse_color;
import vec::push;
type TokenReader = {stream : port<Token>, mut lookahead : option<Token>};
trait util_methods {
fn get() -> Token;
fn unget(-tok : Token);
}
impl util_methods of util_methods for TokenReader {
fn get() -> Token {
alt copy self.lookahead {
some(tok) { self.lookahead = none; copy tok }
none { recv(self.stream) }
}
}
fn unget(-tok : Token) {
assert is_none(self.lookahead);
self.lookahead = some(tok);
}
}
trait parser_methods {
fn parse_element() -> option<~style::Selector>;
fn parse_selector() -> option<~[~Selector]>;
fn parse_description() -> option<~[StyleDeclaration]>;
fn parse_rule() -> option<~style::Rule>;
}
impl parser_methods of parser_methods for TokenReader {
fn parse_element() -> option<~style::Selector> {
// Get the current element type
let elmt_name = alt self.get() {
Element(tag) { copy tag }
Eof { ret none; }
_ { fail ~"Expected an element" }
};
let mut attr_list = ~[];
// Get the attributes associated with that element
loop {
let tok = self.get();
alt tok {
Attr(attr) { push(attr_list, copy attr); }
StartDescription | Descendant | Child | Sibling | Comma {
self.unget(tok);
break;
}
Eof { ret none; }
Element(_) { fail ~"Unexpected second element without relation to first element"; }
EndDescription { fail ~"Unexpected '}'"; }
Description(_, _) { fail ~"Unexpected description"; }
}
}
ret some(~style::Element(elmt_name, attr_list));
}
fn parse_selector() -> option<~[~Selector]> {
let mut sel_list = ~[];
// Collect all the selectors that this rule applies to
loop {
let mut cur_sel;
alt self.parse_element() {
some(elmt) { cur_sel = copy elmt; }
none { ret none; } // we hit an eof in the middle of a rule
}
loop {
let tok = self.get();
let built_sel <- cur_sel;
alt tok {
Descendant {
alt self.parse_element() {
some(elmt) {
let new_sel = copy elmt;
cur_sel <- ~style::Descendant(built_sel, new_sel)
}
none { ret none; }
}
}
Child {
alt self.parse_element() {
some(elmt) {
let new_sel = copy elmt;
cur_sel <- ~style::Child(built_sel, new_sel)
}
none { ret none; }
}
}
Sibling {
alt self.parse_element() {
some(elmt) {
let new_sel = copy elmt;
cur_sel <- ~style::Sibling(built_sel, new_sel)
}
none { ret none; }
}
}
StartDescription {
push(sel_list, built_sel);
self.unget(StartDescription);
break;
}
Comma {
push(sel_list, built_sel);
self.unget(Comma);
break;
}
Attr(_) | EndDescription | Element(_) | Description(_, _) {
fail #fmt["Unexpected token %? in elements", tok];
}
Eof { ret none; }
}
}
// check if we should break out of the nesting loop as well
// TODO: fix this when rust gets labelled loops
let tok = self.get();
alt tok {
StartDescription { break; }
Comma { }
_ { self.unget(tok); }
}
}
ret some(sel_list);
}
fn parse_description() -> option<~[StyleDeclaration]> {
let mut desc_list : ~[StyleDeclaration]= ~[];
// Get the description to be applied to the selector
loop {
let tok = self.get();
alt tok {
EndDescription { break; }
Description(prop, val) {
let desc = alt prop {
// TODO: have color parsing return an option instead of a real value
~"background-color" { parse_color(val).map(|res| BackgroundColor(res)) }
~"color" { parse_color(val).map(|res| TextColor(res)) }
~"display" { parse_display_type(val).map(|res| Display(res)) }
~"font-size" { parse_font_size(val).map(|res| FontSize(res)) }
~"height" { parse_size(val).map(|res| Height(res)) }
~"width" { parse_size(val).map(|res| Width(res)) }
_ { #debug["Recieved unknown style property '%s'", val]; none }
};
desc.map(|res| push(desc_list, res));
}
Eof { ret none; }
StartDescription | Descendant | Child | Sibling | Comma | Element(_) | Attr(_) {
fail #fmt["Unexpected token %? in description", tok];
}
}
}
ret some(desc_list);
}
fn parse_rule() -> option<~style::Rule> {
let sel_list = alt self.parse_selector() {
some(list){ copy list }
none { ret none; }
};
// Get the description to be applied to the selector
let desc_list = alt self.parse_description() {
some(list) { copy list }
none { ret none; }
};
ret some(~(sel_list, desc_list));
}
}
fn build_stylesheet(stream : port<Token>) -> ~[~style::Rule] {
let mut rule_list = ~[];
let reader = {stream : stream, mut lookahead : none};
loop {
alt reader.parse_rule() {
some(rule) { push(rule_list, copy rule); }
none { break; }
}
}
ret rule_list;
}
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