mpw-shell/phase3.lemon

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

%include {

#include "phase3_parser.h"
#include "command.h"
#define LEMON_SUPER phase3
}


%code {
	
std::unique_ptr<phase3> phase3::make() {
	return std::make_unique<yypParser>();
}

bool phase3::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;
		if (e.major == LOOP) return true;
		if (e.major == FOR) return true;
		if (e.major == PIPE) return true;
		if (e.major == PIPE_PIPE) return true;
		if (e.major == AMP_AMP) return true;
	}
	return false;
}


void phase3::parse_accept() {
	error = false;
}

void phase3::parse_failure() {
	error = false;
}

void phase3::syntax_error(int yymajor, std::string &yyminor) {
/*
	switch (yymajor) {
	case END:
		fprintf(stderr, "### MPW Shell - Extra END command.\n");
		break;

	case RPAREN:
		fprintf(stderr, "### MPW Shell - Extra ) command.\n");
		break;

	case ELSE:
	case ELSE_IF:
		fprintf(stderr, "### MPW Shell - ELSE must be within IF ... END.\n");
		break;

	default:
		fprintf(stderr, "### Parse error near %s\n", yyminor.c_str());
		break;
	}
*/

	
	fprintf(stderr, "### MPW Shell - Parse error near %s\n", yymajor ? yyminor.c_str() : "EOF");
	error = true;
}


}

%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(L) ::= compound_list(L) sep.

compound_list(L) ::= compound_list(L) command(C) sep . {
	if (C) L.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(L) PIPE opt_nl command(R). {
	RV = std::make_unique<pipe_command>(std::move(L), std::move(R));
}

command(C) ::= term(C).

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) ::= BREAK(C).         { RV = std::make_unique<break_command>(std::move(C)); }
term(RV) ::= CONTINUE(C).      { RV = std::make_unique<continue_command>(std::move(C)); }
term(RV) ::= EXIT(C).          { RV = std::make_unique<exit_command>(std::move(C)); }
term(C) ::= if_command(C).
term(C) ::= begin_command(C).
term(C) ::= paren_command(C).
term(C) ::= loop_command(C).
term(C) ::= for_command(C).


/* lexer error (mismatched quotes, etc) */
term(RV) ::= ERROR(C). {
	RV = std::make_unique<error_command>(@C, 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 RPAREN.
term(RV) ::= error END.
term(RV) ::= LPAREN error RPAREN.
term(RV) ::= BEGIN error END.
term(RV) ::= IF error END.
term(RV) ::= LOOP error END.
term(RV) ::= FOR error END.
*/

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

paren_list(L) ::= compound_list(L) . 

paren_list(L) ::= compound_list(L) command(C) . {
	L.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));
}


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

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


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