mpw-shell/phase2-parser.lemon

/*
 >, < redirection is handled later, after environment expansion.
 (also, redirection can be in the middle of a command.)
 */

%include {

#include "phase2.h"
#include "command.h"
#define LEMON_SUPER phase2_parser
#include "phase2-parser.h"
}

%code {
	
std::unique_ptr<phase2_parser> phase2_parser::make() {
	return std::make_unique<yypParser>();
}

bool phase2_parser::continuation() const {
	yypParser *self = (yypParser *)this;

	for (const auto &e : *self) {
		if (e.major == BEGIN) return true;
		if (e.major == LPAREN) return true;
		if (e.major == IF) return true;
		if (e.major == AMP_AMP) return true;
		if (e.major == PIPE_PIPE) return true;
	}
	return false;
}

}

%left PIPE_PIPE AMP_AMP.
%left PIPE.

%token_type {std::string}
%default_type {command_ptr}

%type start {void}
%type command_list {void}

/* these are put into a queue for immmediate execution */


start ::= command_list.


command_list ::= .
command_list ::= command_list sep .
command_list ::= command_list command(C) sep . {
	if (C) command_queue.emplace_back(std::move(C));
}



/*
 compound_list is identical to command_list, but it is not executed immediately.
 */

%type compound_list { command_ptr_vector }


compound_list ::= .
compound_list(RV) ::= compound_list(L) sep. {
	RV = std::move(L);
}

compound_list(RV) ::= compound_list(L) command(C) sep . {
	RV = std::move(L);
	if (C) RV.emplace_back(std::move(C));
}


sep ::= SEMI.
sep ::= NL.


%type command { command_ptr }

/* nb -- ||, &&, | -- both sides are optional. This does not. */

command(RV) ::= command(L) PIPE_PIPE opt_nl command(R). {
	RV = std::make_unique<or_command>(std::move(L), std::move(R));
}

command(RV) ::= command(L) AMP_AMP opt_nl command(R). {
	RV = std::make_unique<and_command>(std::move(L), std::move(R));
}

/*
command(RV) ::= command PIPE opt_nl command. {
	RV = std::make_unique<pipe_command>(std::move(L), std::move(R));
}
*/

command(RV) ::= term(T). { RV = std::move(T); }

term(RV) ::= COMMAND(C).       { RV = std::make_unique<simple_command>(std::move(C)); }
term(RV) ::= EVALUATE(C).      { RV = std::make_unique<evaluate_command>(std::move(C)); }
term(RV) ::= if_command(C).    { RV = std::move(C); }
term(RV) ::= begin_command(C). { RV = std::move(C); }
term(RV) ::= paren_command(C). { RV = std::move(C); }

/*
 * fall back to an end error.  w/o fallback, it will cause a parse conflict.
 */
 /*
%fallback ERROR END RPAREN ELSE ELSE_IF.

term(RV) ::= ERROR(C). {
	RV = std::make_unique<error_command>(@C, std::move(C));
}
*/


/* compound list ends with a separator.  paren command does not need the final separator */
%type paren_list { command_ptr_vector }

paren_list(RV) ::= compound_list(L) . {
	RV = std::move(L);
}

paren_list(RV) ::= compound_list(L) command(C) . {
	RV = std::move(L);
	RV.emplace_back(std::move(C));
}

paren_command(RV) ::= LPAREN(T) paren_list(L) RPAREN(E). {
	RV = std::make_unique<begin_command>(@T, std::move(L), std::move(T), std::move(E));
}


begin_command(RV) ::= BEGIN(T) sep compound_list(L) END(E). {
	RV = std::make_unique<begin_command>(@T, std::move(L), std::move(T), std::move(E));
}

if_command(RV) ::= IF(I) sep compound_list(L) END(E). {

	if_command::clause_vector_type v;
	v.emplace_back(std::make_unique<if_else_clause>(IF, std::move(L), std::move(I)));

	RV = std::make_unique<if_command>(
		std::move(v),
		std::move(E)
	);

}

if_command(RV) ::= IF(I) sep compound_list(L) else_command(EC) END(E). {

	if_command::clause_vector_type v;
	v.emplace_back(std::make_unique<if_else_clause>(IF, std::move(L), std::move(I)));
	for(auto &c : EC) { v.emplace_back(std::move(c)); }

	RV = std::make_unique<if_command>(
		std::move(v), std::move(E));	
}

%token_class else ELSE_IF ELSE.

%type else_command { if_command::clause_vector_type }
else_command(RV) ::= else(E) sep compound_list(L). {
	RV.emplace_back(std::make_unique<if_else_clause>(@E, std::move(L), std::move(E)));
}


else_command(RV) ::= else_command(EC) else(E) sep compound_list(L). {
	RV = std::move(EC);
	RV.emplace_back(std::make_unique<if_else_clause>(@E, std::move(L), std::move(E)));
}


opt_nl ::= .
opt_nl ::= opt_nl NL .