ladybird/Userland/Shell/Parser.h
2021-01-12 12:04:07 +01:00

263 lines
8.2 KiB
C++

/*
* Copyright (c) 2020, the SerenityOS developers.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include "AST.h"
#include <AK/Function.h>
#include <AK/RefPtr.h>
#include <AK/String.h>
#include <AK/StringBuilder.h>
#include <AK/Vector.h>
namespace Shell {
class Parser {
public:
Parser(StringView input)
: m_input(move(input))
{
}
RefPtr<AST::Node> parse();
struct SavedOffset {
size_t offset;
AST::Position::Line line;
};
SavedOffset save_offset() const;
private:
constexpr static size_t max_allowed_nested_rule_depth = 2048;
RefPtr<AST::Node> parse_toplevel();
RefPtr<AST::Node> parse_sequence();
RefPtr<AST::Node> parse_function_decl();
RefPtr<AST::Node> parse_and_logical_sequence();
RefPtr<AST::Node> parse_or_logical_sequence();
RefPtr<AST::Node> parse_variable_decls();
RefPtr<AST::Node> parse_pipe_sequence();
RefPtr<AST::Node> parse_command();
RefPtr<AST::Node> parse_control_structure();
RefPtr<AST::Node> parse_continuation_control();
RefPtr<AST::Node> parse_for_loop();
RefPtr<AST::Node> parse_loop_loop();
RefPtr<AST::Node> parse_if_expr();
RefPtr<AST::Node> parse_subshell();
RefPtr<AST::Node> parse_match_expr();
AST::MatchEntry parse_match_entry();
RefPtr<AST::Node> parse_match_pattern();
RefPtr<AST::Node> parse_redirection();
RefPtr<AST::Node> parse_list_expression();
RefPtr<AST::Node> parse_expression();
RefPtr<AST::Node> parse_string_composite();
RefPtr<AST::Node> parse_string();
RefPtr<AST::Node> parse_doublequoted_string_inner();
RefPtr<AST::Node> parse_variable();
RefPtr<AST::Node> parse_evaluate();
RefPtr<AST::Node> parse_comment();
RefPtr<AST::Node> parse_bareword();
RefPtr<AST::Node> parse_glob();
RefPtr<AST::Node> parse_brace_expansion();
RefPtr<AST::Node> parse_brace_expansion_spec();
template<typename A, typename... Args>
NonnullRefPtr<A> create(Args... args);
bool at_end() const { return m_input.length() <= m_offset; }
char peek();
char consume();
bool expect(char);
bool expect(const StringView&);
bool next_is(const StringView&);
void restore_to(size_t offset, AST::Position::Line line)
{
m_offset = offset;
m_line = move(line);
}
AST::Position::Line line() const { return m_line; }
StringView consume_while(Function<bool(char)>);
struct ScopedOffset {
ScopedOffset(Vector<size_t>& offsets, Vector<AST::Position::Line>& lines, size_t offset, size_t lineno, size_t linecol)
: offsets(offsets)
, lines(lines)
, offset(offset)
, line({ lineno, linecol })
{
offsets.append(offset);
lines.append(line);
}
~ScopedOffset()
{
auto last = offsets.take_last();
ASSERT(last == offset);
auto last_line = lines.take_last();
ASSERT(last_line == line);
}
Vector<size_t>& offsets;
Vector<AST::Position::Line>& lines;
size_t offset;
AST::Position::Line line;
};
void restore_to(const ScopedOffset& offset) { restore_to(offset.offset, offset.line); }
OwnPtr<ScopedOffset> push_start();
StringView m_input;
size_t m_offset { 0 };
AST::Position::Line m_line { 0, 0 };
Vector<size_t> m_rule_start_offsets;
Vector<AST::Position::Line> m_rule_start_lines;
bool m_is_in_brace_expansion_spec { false };
bool m_continuation_controls_allowed { false };
};
#if 0
constexpr auto the_grammar = R"(
toplevel :: sequence?
sequence :: variable_decls? or_logical_sequence terminator sequence
| variable_decls? or_logical_sequence '&' sequence
| variable_decls? or_logical_sequence
| variable_decls? function_decl (terminator sequence)?
| variable_decls? terminator sequence
function_decl :: identifier '(' (ws* identifier)* ')' ws* '{' [!c] toplevel '}'
or_logical_sequence :: and_logical_sequence '|' '|' and_logical_sequence
| and_logical_sequence
and_logical_sequence :: pipe_sequence '&' '&' and_logical_sequence
| pipe_sequence
terminator :: ';'
| '\n'
variable_decls :: identifier '=' expression (' '+ variable_decls)? ' '*
| identifier '=' '(' pipe_sequence ')' (' '+ variable_decls)? ' '*
pipe_sequence :: command '|' pipe_sequence
| command
| control_structure '|' pipe_sequence
| control_structure
control_structure[c] :: for_expr
| loop_expr
| if_expr
| subshell
| match_expr
| ?c: continuation_control
continuation_control :: 'break'
| 'continue'
for_expr :: 'for' ws+ (identifier ' '+ 'in' ws*)? expression ws+ '{' [c] toplevel '}'
loop_expr :: 'loop' ws* '{' [c] toplevel '}'
if_expr :: 'if' ws+ or_logical_sequence ws+ '{' toplevel '}' else_clause?
else_clause :: else '{' toplevel '}'
| else if_expr
subshell :: '{' toplevel '}'
match_expr :: 'match' ws+ expression ws* ('as' ws+ identifier)? '{' match_entry* '}'
match_entry :: match_pattern ws* (as identifier_list)? '{' toplevel '}'
identifier_list :: '(' (identifier ws*)* ')'
match_pattern :: expression (ws* '|' ws* expression)*
command :: redirection command
| list_expression command?
redirection :: number? '>'{1,2} ' '* string_composite
| number? '<' ' '* string_composite
| number? '>' '&' number
| number? '>' '&' '-'
list_expression :: ' '* expression (' '+ list_expression)?
expression :: evaluate expression?
| string_composite expression?
| comment expression?
| '(' list_expression ')' expression?
evaluate :: '$' '(' pipe_sequence ')'
| '$' expression {eval / dynamic resolve}
string_composite :: string string_composite?
| variable string_composite?
| bareword string_composite?
| glob string_composite?
| brace_expansion string_composite?
string :: '"' dquoted_string_inner '"'
| "'" [^']* "'"
dquoted_string_inner :: '\' . dquoted_string_inner? {concat}
| variable dquoted_string_inner? {compose}
| . dquoted_string_inner?
| '\' 'x' digit digit dquoted_string_inner?
| '\' [abefrn] dquoted_string_inner?
variable :: '$' identifier
| '$' '$'
| '$' '?'
| '$' '*'
| '$' '#'
| ...
comment :: '#' [^\n]*
bareword :: [^"'*$&#|()[\]{} ?;<>] bareword?
| '\' [^"'*$&#|()[\]{} ?;<>] bareword?
bareword_with_tilde_expansion :: '~' bareword?
glob :: [*?] bareword?
| bareword [*?]
brace_expansion :: '{' brace_expansion_spec '}'
brace_expansion_spec :: expression? (',' expression?)*
| expression '..' expression
)";
#endif
}