ladybird/Userland/Shell/Parser.h
implicitfield 4b60a99573 Shell: Remove '#' from the list of acceptable bareword characters
This stops the shell from always interpreting '#' as the start of a
comment in non-Posix mode.
2023-10-29 01:35:40 +03:30

329 lines
10 KiB
C++

/*
* Copyright (c) 2020, the SerenityOS developers.
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#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, bool interactive = false)
: m_input(move(input))
, m_in_interactive_mode(interactive)
{
}
RefPtr<AST::Node> parse();
/// Parse the given string *as* an expression
/// that is to forcefully enclose it in double-quotes.
RefPtr<AST::Node> parse_as_single_expression();
Vector<NonnullRefPtr<AST::Node>> parse_as_multiple_expressions();
struct SavedOffset {
size_t offset;
AST::Position::Line line;
};
SavedOffset save_offset() const;
private:
enum class ShouldReadMoreSequences {
Yes,
No,
};
enum class StringEndCondition {
DoubleQuote,
Heredoc,
};
struct SequenceParseResult {
Vector<NonnullRefPtr<AST::Node>> entries;
Vector<AST::Position, 1> separator_positions;
ShouldReadMoreSequences decision;
};
struct HeredocInitiationRecord {
String end;
RefPtr<AST::Heredoc> node;
bool interpolate { false };
bool deindent { false };
};
constexpr static size_t max_allowed_nested_rule_depth = 2048;
RefPtr<AST::Node> parse_toplevel();
SequenceParseResult 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();
Optional<Regex<ECMA262>> parse_regex_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_string_inner(StringEndCondition);
RefPtr<AST::Node> parse_variable();
RefPtr<AST::Node> parse_variable_ref();
RefPtr<AST::Slice> parse_slice();
RefPtr<AST::Node> parse_evaluate();
RefPtr<AST::Node> parse_history_designator();
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();
RefPtr<AST::Node> parse_immediate_expression();
RefPtr<AST::Node> parse_heredoc_initiation_record();
bool parse_heredoc_entries();
template<typename A, typename... Args>
NonnullRefPtr<A> create(Args&&... args);
void set_end_condition(OwnPtr<Function<bool()>> condition) { m_end_condition = move(condition); }
bool at_end() const
{
if (m_end_condition && (*m_end_condition)())
return true;
return m_input.length() <= m_offset;
}
char peek();
char consume();
bool expect(char);
bool expect(StringView);
bool next_is(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 Offset {
size_t offset;
AST::Position::Line line;
};
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();
VERIFY(last == offset);
auto last_line = lines.take_last();
VERIFY(last_line == line);
}
Vector<size_t>& offsets;
Vector<AST::Position::Line>& lines;
size_t offset;
AST::Position::Line line;
};
void restore_to(ScopedOffset const& offset) { restore_to(offset.offset, offset.line); }
OwnPtr<ScopedOffset> push_start();
Offset current_position();
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;
OwnPtr<Function<bool()>> m_end_condition;
Vector<HeredocInitiationRecord> m_heredoc_initiations;
Vector<char> m_extra_chars_not_allowed_in_barewords;
bool m_is_in_brace_expansion_spec { false };
bool m_continuation_controls_allowed { false };
bool m_in_interactive_mode { 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' [?!heredoc_stack.is_empty] heredoc_entries
heredoc_entries :: { .*? (heredoc_entry) '\n' } [each heredoc_entries]
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+ (('index' ' '+ identifier ' '+)? 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 '}'
| regex_pattern ws* '{' toplevel '}'
identifier_list :: '(' (identifier ws*)* ')'
regex_pattern :: regex_pattern (ws* '|' ws* regex_pattern)*
match_pattern :: expression (ws* '|' ws* expression)*
regex_pattern :: '(?:' .* ')' { enclosed string must contain balanced parentheses }
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?
| immediate_expression expression?
| history_designator expression?
| '(' list_expression ')' expression?
evaluate :: '$' '(' pipe_sequence ')'
| '$' [lookahead != '('] expression {eval / dynamic resolve}
string_composite :: string string_composite?
| variable string_composite?
| bareword string_composite?
| glob string_composite?
| brace_expansion string_composite?
| heredoc_initiator string_composite? {append to heredoc_entries}
heredoc_initiator :: '<' '<' '-' bareword {*bareword, interpolate, no deindent}
| '<' '<' '-' "'" [^']* "'" {*string, no interpolate, no deindent}
| '<' '<' '~' bareword {*bareword, interpolate, deindent}
| '<' '<' '~' "'" [^']* "'" {*bareword, no interpolate, deindent}
string :: '"' dquoted_string_inner '"'
| "'" [^']* "'"
dquoted_string_inner :: '\' . dquoted_string_inner? {concat}
| variable dquoted_string_inner? {compose}
| . dquoted_string_inner?
| '\' 'x' xdigit*2 dquoted_string_inner?
| '\' 'u' xdigit*8 dquoted_string_inner?
| '\' [abefrnt] dquoted_string_inner?
variable :: variable_ref slice?
variable_ref :: '$' identifier
| '$' '$'
| '$' '?'
| '$' '*'
| '$' '#'
| ...
slice :: '[' brace_expansion_spec ']'
comment :: (?<!\w) '#' .*
immediate_expression :: '$' '{' immediate_function expression* '}'
immediate_function :: identifier { predetermined list of names, see Shell.h:ENUMERATE_SHELL_IMMEDIATE_FUNCTIONS }
history_designator :: '!' event_selector (':' word_selector_composite)?
event_selector :: '!' {== '-0'}
| '?' bareword '?'
| bareword {number: index, otherwise: lookup}
word_selector_composite :: word_selector ('-' word_selector)?
word_selector :: number
| '^' {== 0}
| '$' {== end}
bareword :: [^"'*$&|()[\]{} ?;<>] bareword?
| '\' [^"'*$&|()[\]{} ?;<>] bareword?
bareword_with_tilde_expansion :: '~' bareword?
glob :: [*?] bareword?
| bareword [*?]
brace_expansion :: '{' brace_expansion_spec '}'
brace_expansion_spec :: expression? (',' expression?)*
| expression '..' expression
)";
#endif
}