ledger/src/op.cc
2012-05-20 04:48:05 -05:00

982 lines
26 KiB
C++

/*
* Copyright (c) 2003-2012, John Wiegley. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - 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.
*
* - Neither the name of New Artisans LLC nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* 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
* OWNER 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.
*/
#include <system.hh>
#include "op.h"
#include "scope.h"
#include "commodity.h"
#include "pool.h"
namespace ledger {
void intrusive_ptr_add_ref(const expr_t::op_t * op)
{
op->acquire();
}
void intrusive_ptr_release(const expr_t::op_t * op)
{
op->release();
}
value_t split_cons_expr(expr_t::ptr_op_t op)
{
if (op->kind == expr_t::op_t::O_CONS) {
value_t seq;
seq.push_back(expr_value(op->left()));
expr_t::ptr_op_t next = op->right();
while (next) {
expr_t::ptr_op_t value_op;
if (next->kind == expr_t::op_t::O_CONS) {
value_op = next->left();
next = next->has_right() ? next->right() : NULL;
} else {
value_op = next;
next = NULL;
}
seq.push_back(expr_value(value_op));
}
return seq;
} else {
return expr_value(op);
}
}
namespace {
inline void check_type_context(scope_t& scope, value_t& result)
{
if (scope.type_required() &&
scope.type_context() != value_t::VOID &&
result.type() != scope.type_context()) {
throw_(calc_error,
_f("Expected return of %1%, but received %2%")
% result.label(scope.type_context())
% result.label());
}
}
}
expr_t::ptr_op_t expr_t::op_t::compile(scope_t& scope, const int depth,
scope_t * param_scope)
{
scope_t * scope_ptr = &scope;
unique_ptr<scope_t> bound_scope;
expr_t::ptr_op_t result;
#if DEBUG_ON
if (SHOW_DEBUG("expr.compile")) {
for (int i = 0; i < depth; i++)
ledger::_log_buffer << '.';
DEBUG("expr.compile", "");
}
#endif
assert(kind < LAST);
if (is_ident()) {
DEBUG("expr.compile", "Lookup: " << as_ident() << " in " << scope_ptr);
ptr_op_t def;
if (param_scope)
def = param_scope->lookup(symbol_t::FUNCTION, as_ident());
if (! def)
def = scope_ptr->lookup(symbol_t::FUNCTION, as_ident());
if (def) {
// Identifier references are first looked up at the point of
// definition, and then at the point of every use if they could
// not be found there.
#if DEBUG_ON
if (SHOW_DEBUG("expr.compile")) {
DEBUG("expr.compile", "Found definition:");
def->dump(*_log_stream, 0);
}
#endif // DEBUG_ON
result = copy(def);
}
else if (left()) {
result = copy();
}
else {
result = this;
}
}
else if (is_scope()) {
shared_ptr<scope_t> subscope(new symbol_scope_t(*scope_t::empty_scope));
set_scope(subscope);
bound_scope.reset(new bind_scope_t(*scope_ptr, *subscope.get()));
scope_ptr = bound_scope.get();
}
else if (kind < TERMINALS) {
result = this;
}
else if (kind == O_DEFINE) {
switch (left()->kind) {
case IDENT: {
ptr_op_t node(right()->compile(*scope_ptr, depth + 1, param_scope));
DEBUG("expr.compile",
"Defining " << left()->as_ident() << " in " << scope_ptr);
scope_ptr->define(symbol_t::FUNCTION, left()->as_ident(), node);
break;
}
case O_CALL:
if (left()->left()->is_ident()) {
ptr_op_t node(new op_t(op_t::O_LAMBDA));
node->set_left(left()->right());
node->set_right(right());
node = node->compile(*scope_ptr, depth + 1, param_scope);
DEBUG("expr.compile",
"Defining " << left()->left()->as_ident() << " in " << scope_ptr);
scope_ptr->define(symbol_t::FUNCTION, left()->left()->as_ident(), node);
break;
}
// fall through...
default:
throw_(compile_error, _("Invalid function definition"));
}
result = wrap_value(NULL_VALUE);
}
else if (kind == O_LAMBDA) {
symbol_scope_t params(param_scope ? *param_scope : *scope_t::empty_scope);
for (ptr_op_t sym = left();
sym;
sym = sym->has_right() ? sym->right() : NULL) {
ptr_op_t varname = sym->kind == O_CONS ? sym->left() : sym;
if (! varname->is_ident()) {
std::ostringstream buf;
varname->dump(buf, 0);
throw_(calc_error,
_f("Invalid function or lambda parameter: %1%") % buf.str());
} else {
DEBUG("expr.compile",
"Defining function parameter " << varname->as_ident());
params.define(symbol_t::FUNCTION, varname->as_ident(),
new op_t(PLUG));
}
}
ptr_op_t rhs(right()->compile(*scope_ptr, depth + 1, &params));
if (rhs == right())
result = this;
else
result = copy(left(), rhs);
}
if (! result) {
if (! left())
throw_(calc_error, _("Syntax error"));
ptr_op_t lhs(left()->compile(*scope_ptr, depth + 1, param_scope));
ptr_op_t rhs(kind > UNARY_OPERATORS && has_right() ?
(kind == O_LOOKUP ? right() :
right()->compile(*scope_ptr, depth + 1, param_scope)) : NULL);
if (lhs == left() && (! rhs || rhs == right())) {
result = this;
} else {
ptr_op_t intermediate(copy(lhs, rhs));
// Reduce constants immediately if possible
if ((! lhs || lhs->is_value()) && (! rhs || rhs->is_value()))
result = wrap_value(intermediate->calc(*scope_ptr, NULL, depth + 1));
else
result = intermediate;
}
}
#if DEBUG_ON
if (SHOW_DEBUG("expr.compile")) {
for (int i = 0; i < depth; i++)
ledger::_log_buffer << '.';
DEBUG("expr.compile", "");
}
#endif
return result;
}
namespace {
expr_t::ptr_op_t lookup_ident(expr_t::ptr_op_t op, scope_t& scope)
{
expr_t::ptr_op_t def = op->left();
// If no definition was pre-compiled for this identifier, look it up
// in the current scope.
if (! def || def->kind == expr_t::op_t::PLUG) {
DEBUG("scope.symbols", "Looking for IDENT '" << op->as_ident() << "'");
def = scope.lookup(symbol_t::FUNCTION, op->as_ident());
}
if (! def)
throw_(calc_error, _f("Unknown identifier '%1%'") % op->as_ident());
return def;
}
}
value_t expr_t::op_t::calc(scope_t& scope, ptr_op_t * locus, const int depth)
{
try {
value_t result;
#if DEBUG_ON
if (SHOW_DEBUG("expr.calc")) {
for (int i = 0; i < depth; i++)
ledger::_log_buffer << '.';
ledger::_log_buffer << op_context(this) << " => ...";
DEBUG("expr.calc", "");
}
#endif
switch (kind) {
case VALUE:
result = as_value();
break;
case O_DEFINE:
result = NULL_VALUE;
break;
case IDENT:
if (ptr_op_t definition = lookup_ident(this, scope)) {
// Evaluating an identifier is the same as calling its definition
// directly
result = definition->calc(scope, locus, depth + 1);
check_type_context(scope, result);
}
break;
case FUNCTION: {
// Evaluating a FUNCTION is the same as calling it directly; this
// happens when certain functions-that-look-like-variables (such as
// "amount") are resolved.
call_scope_t call_args(scope, locus, depth + 1);
result = as_function()(call_args);
check_type_context(scope, result);
break;
}
case SCOPE:
assert(! is_scope_unset());
if (is_scope_unset()) {
symbol_scope_t subscope(scope);
result = left()->calc(subscope, locus, depth + 1);
} else {
bind_scope_t bound_scope(scope, *as_scope());
result = left()->calc(bound_scope, locus, depth + 1);
}
break;
case O_LOOKUP: {
context_scope_t context_scope(scope, value_t::SCOPE);
bool scope_error = true;
if (value_t obj = left()->calc(context_scope, locus, depth + 1)) {
if (obj.is_scope() && obj.as_scope() != NULL) {
bind_scope_t bound_scope(scope, *obj.as_scope());
result = right()->calc(bound_scope, locus, depth + 1);
scope_error = false;
}
}
if (scope_error)
throw_(calc_error, _("Left operand does not evaluate to an object"));
break;
}
case O_CALL:
result = calc_call(scope, locus, depth);
check_type_context(scope, result);
break;
case O_LAMBDA:
result = expr_value(this);
break;
case O_MATCH:
result = (right()->calc(scope, locus, depth + 1).as_mask()
.match(left()->calc(scope, locus, depth + 1).to_string()));
break;
case O_EQ:
result = (left()->calc(scope, locus, depth + 1) ==
right()->calc(scope, locus, depth + 1));
break;
case O_LT:
result = (left()->calc(scope, locus, depth + 1) <
right()->calc(scope, locus, depth + 1));
break;
case O_LTE:
result = (left()->calc(scope, locus, depth + 1) <=
right()->calc(scope, locus, depth + 1));
break;
case O_GT:
result = (left()->calc(scope, locus, depth + 1) >
right()->calc(scope, locus, depth + 1));
break;
case O_GTE:
result = (left()->calc(scope, locus, depth + 1) >=
right()->calc(scope, locus, depth + 1));
break;
case O_ADD:
result = (left()->calc(scope, locus, depth + 1) +
right()->calc(scope, locus, depth + 1));
break;
case O_SUB:
result = (left()->calc(scope, locus, depth + 1) -
right()->calc(scope, locus, depth + 1));
break;
case O_MUL:
result = (left()->calc(scope, locus, depth + 1) *
right()->calc(scope, locus, depth + 1));
break;
case O_DIV:
result = (left()->calc(scope, locus, depth + 1) /
right()->calc(scope, locus, depth + 1));
break;
case O_NEG:
result = left()->calc(scope, locus, depth + 1).negated();
break;
case O_NOT:
result = ! left()->calc(scope, locus, depth + 1);
break;
case O_AND:
if (left()->calc(scope, locus, depth + 1))
result = right()->calc(scope, locus, depth + 1);
else
result = false;
break;
case O_OR:
if (value_t temp = left()->calc(scope, locus, depth + 1))
result = temp;
else
result = right()->calc(scope, locus, depth + 1);
break;
case O_QUERY:
assert(right());
assert(right()->kind == O_COLON);
if (value_t temp = left()->calc(scope, locus, depth + 1))
result = right()->left()->calc(scope, locus, depth + 1);
else
result = right()->right()->calc(scope, locus, depth + 1);
break;
case O_COLON:
assert("We should never calculate an O_COLON operator" == NULL);
break;
case O_CONS:
result = calc_cons(scope, locus, depth);
break;
case O_SEQ:
result = calc_seq(scope, locus, depth);
break;
default:
throw_(calc_error, _f("Unexpected expr node '%1%'") % op_context(this));
}
#if DEBUG_ON
if (SHOW_DEBUG("expr.calc")) {
for (int i = 0; i < depth; i++)
ledger::_log_buffer << '.';
ledger::_log_buffer << op_context(this) << " => ";
result.dump(ledger::_log_buffer, true);
DEBUG("expr.calc", "");
}
#endif
return result;
}
catch (const std::exception&) {
if (locus && ! *locus)
*locus = this;
throw;
}
}
namespace {
expr_t::ptr_op_t find_definition(expr_t::ptr_op_t op, scope_t& scope,
expr_t::ptr_op_t * locus, const int depth,
int recursion_depth = 0)
{
// If the object we are apply call notation to is a FUNCTION value
// or a O_LAMBDA expression, then this is the object we want to
// call.
if (op->is_function() || op->kind == expr_t::op_t::O_LAMBDA)
return op;
if (recursion_depth > 256)
throw_(value_error, _("Function recursion_depth too deep (> 256)"));
// If it's an identifier, look up its definition and see if it's a
// function.
if (op->is_ident())
return find_definition(lookup_ident(op, scope), scope,
locus, depth, recursion_depth + 1);
// Value objects might be callable if they contain an expression.
if (op->is_value()) {
value_t def(op->as_value());
if (is_expr(def))
return find_definition(as_expr(def), scope, locus, depth,
recursion_depth + 1);
else
throw_(value_error, _f("Cannot call %1% as a function") % def.label());
}
// Resolve ordinary expressions.
return find_definition(expr_t::op_t::wrap_value(op->calc(scope, locus,
depth + 1)),
scope, locus, depth + 1, recursion_depth + 1);
}
value_t call_lambda(expr_t::ptr_op_t func, scope_t& scope,
call_scope_t& call_args, expr_t::ptr_op_t * locus,
const int depth)
{
std::size_t args_index(0);
std::size_t args_count(call_args.size());
symbol_scope_t args_scope(*scope_t::empty_scope);
for (expr_t::ptr_op_t sym = func->left();
sym;
sym = sym->has_right() ? sym->right() : NULL) {
expr_t::ptr_op_t varname =
sym->kind == expr_t::op_t::O_CONS ? sym->left() : sym;
if (! varname->is_ident()) {
throw_(calc_error, _("Invalid function definition"));
}
else if (args_index == args_count) {
DEBUG("expr.calc", "Defining function argument as null: "
<< varname->as_ident());
args_scope.define(symbol_t::FUNCTION, varname->as_ident(),
expr_t::op_t::wrap_value(NULL_VALUE));
}
else {
DEBUG("expr.calc", "Defining function argument from call_args: "
<< varname->as_ident());
args_scope.define(symbol_t::FUNCTION, varname->as_ident(),
expr_t::op_t::wrap_value(call_args[args_index++]));
}
}
if (args_index < args_count)
throw_(calc_error,
_f("Too few arguments in function call (saw %1%, wanted %2%)")
% args_count % args_index);
if (func->right()->is_scope()) {
bind_scope_t outer_scope(scope, *func->right()->as_scope());
bind_scope_t bound_scope(outer_scope, args_scope);
return func->right()->left()->calc(bound_scope, locus, depth + 1);
} else {
return func->right()->calc(args_scope, locus, depth + 1);
}
}
}
value_t expr_t::op_t::call(const value_t& args, scope_t& scope,
ptr_op_t * locus, const int depth)
{
call_scope_t call_args(scope, locus, depth + 1);
call_args.set_args(args);
if (is_function())
return as_function()(call_args);
else if (kind == O_LAMBDA)
return call_lambda(this, scope, call_args, locus, depth);
else
return find_definition(this, scope, locus, depth)
->calc(call_args, locus, depth);
}
value_t expr_t::op_t::calc_call(scope_t& scope, ptr_op_t * locus,
const int depth)
{
ptr_op_t func = left();
string name = func->is_ident() ? func->as_ident() : "<value expr>";
func = find_definition(func, scope, locus, depth);
call_scope_t call_args(scope, locus, depth + 1);
if (has_right())
call_args.set_args(split_cons_expr(right()));
try {
if (func->is_function()) {
return func->as_function()(call_args);
} else {
assert(func->kind == O_LAMBDA);
return call_lambda(func, scope, call_args, locus, depth);
}
}
catch (const std::exception&) {
add_error_context(_f("While calling function '%1% %2%':") % name
% call_args.args);
throw;
}
}
value_t expr_t::op_t::calc_cons(scope_t& scope, ptr_op_t * locus,
const int depth)
{
value_t result = left()->calc(scope, locus, depth + 1);
if (has_right()) {
value_t temp;
temp.push_back(result);
ptr_op_t next = right();
while (next) {
ptr_op_t value_op;
if (next->kind == O_CONS) {
value_op = next->left();
next = next->has_right() ? next->right() : NULL;
} else {
value_op = next;
next = NULL;
}
temp.push_back(value_op->calc(scope, locus, depth + 1));
}
result = temp;
}
return result;
}
value_t expr_t::op_t::calc_seq(scope_t& scope, ptr_op_t * locus,
const int depth)
{
// An O_SEQ is very similar to an O_CONS except that only the last
// result value in the series is kept. O_CONS builds up a list.
//
// Another feature of O_SEQ is that it pushes a new symbol scope onto
// the stack. We evaluate the left side here to catch any
// side-effects, such as definitions in the case of 'x = 1; x'.
value_t result = left()->calc(scope, locus, depth + 1);
if (has_right()) {
ptr_op_t next = right();
while (next) {
ptr_op_t value_op;
if (next->kind == O_SEQ) {
value_op = next->left();
next = next->right();
} else {
value_op = next;
next = NULL;
}
result = value_op->calc(scope, locus, depth + 1);
}
}
return result;
}
namespace {
bool print_cons(std::ostream& out, const expr_t::const_ptr_op_t op,
const expr_t::op_t::context_t& context)
{
bool found = false;
assert(op->left());
if (op->left()->print(out, context))
found = true;
if (op->has_right()) {
out << ", ";
if (op->right()->kind == expr_t::op_t::O_CONS)
found = print_cons(out, op->right(), context);
else if (op->right()->print(out, context))
found = true;
}
return found;
}
bool print_seq(std::ostream& out, const expr_t::const_ptr_op_t op,
const expr_t::op_t::context_t& context)
{
bool found = false;
assert(op->left());
if (op->left()->print(out, context))
found = true;
if (op->has_right()) {
out << "; ";
if (op->right()->kind == expr_t::op_t::O_SEQ)
found = print_seq(out, op->right(), context);
else if (op->right()->print(out, context))
found = true;
}
return found;
}
}
bool expr_t::op_t::print(std::ostream& out, const context_t& context) const
{
bool found = false;
if (context.start_pos && this == context.op_to_find) {
*context.start_pos = out.tellp();
*context.start_pos -= 1;
found = true;
}
string symbol;
if (kind > TERMINALS && (kind != O_CALL && kind != O_DEFINE))
out << '(';
switch (kind) {
case VALUE:
as_value().dump(out, context.relaxed);
break;
case IDENT:
out << as_ident();
break;
case FUNCTION:
out << "<FUNCTION>";
break;
case SCOPE:
if (left() && left()->print(out, context))
found = true;
break;
case O_NOT:
out << "! ";
if (left() && left()->print(out, context))
found = true;
break;
case O_NEG:
out << "- ";
if (left() && left()->print(out, context))
found = true;
break;
case O_ADD:
if (left() && left()->print(out, context))
found = true;
out << " + ";
if (has_right() && right()->print(out, context))
found = true;
break;
case O_SUB:
if (left() && left()->print(out, context))
found = true;
out << " - ";
if (has_right() && right()->print(out, context))
found = true;
break;
case O_MUL:
if (left() && left()->print(out, context))
found = true;
out << " * ";
if (has_right() && right()->print(out, context))
found = true;
break;
case O_DIV:
if (left() && left()->print(out, context))
found = true;
out << " / ";
if (has_right() && right()->print(out, context))
found = true;
break;
case O_EQ:
if (left() && left()->print(out, context))
found = true;
out << " == ";
if (has_right() && right()->print(out, context))
found = true;
break;
case O_LT:
if (left() && left()->print(out, context))
found = true;
out << " < ";
if (has_right() && right()->print(out, context))
found = true;
break;
case O_LTE:
if (left() && left()->print(out, context))
found = true;
out << " <= ";
if (has_right() && right()->print(out, context))
found = true;
break;
case O_GT:
if (left() && left()->print(out, context))
found = true;
out << " > ";
if (has_right() && right()->print(out, context))
found = true;
break;
case O_GTE:
if (left() && left()->print(out, context))
found = true;
out << " >= ";
if (has_right() && right()->print(out, context))
found = true;
break;
case O_AND:
if (left() && left()->print(out, context))
found = true;
out << " & ";
if (has_right() && right()->print(out, context))
found = true;
break;
case O_OR:
if (left() && left()->print(out, context))
found = true;
out << " | ";
if (has_right() && right()->print(out, context))
found = true;
break;
case O_QUERY:
if (left() && left()->print(out, context))
found = true;
out << " ? ";
if (has_right() && right()->print(out, context))
found = true;
break;
case O_COLON:
if (left() && left()->print(out, context))
found = true;
out << " : ";
if (has_right() && right()->print(out, context))
found = true;
break;
case O_CONS:
found = print_cons(out, this, context);
break;
case O_SEQ:
found = print_seq(out, this, context);
break;
case O_DEFINE:
if (left() && left()->print(out, context))
found = true;
out << " = ";
if (has_right() && right()->print(out, context))
found = true;
break;
case O_LOOKUP:
if (left() && left()->print(out, context))
found = true;
out << ".";
if (has_right() && right()->print(out, context))
found = true;
break;
case O_LAMBDA:
if (left() && left()->print(out, context))
found = true;
out << " -> ";
if (has_right() && right()->print(out, context))
found = true;
break;
case O_CALL:
if (left() && left()->print(out, context))
found = true;
if (has_right()) {
if (right()->kind == O_CONS) {
if (right()->print(out, context))
found = true;
} else {
out << "(";
if (has_right() && right()->print(out, context))
found = true;
out << ")";
}
} else {
out << "()";
}
break;
case O_MATCH:
if (left() && left()->print(out, context))
found = true;
out << " =~ ";
if (has_right() && right()->print(out, context))
found = true;
break;
case LAST:
default:
assert(false);
break;
}
if (kind > TERMINALS && (kind != O_CALL && kind != O_DEFINE))
out << ')';
if (! symbol.empty()) {
if (commodity_pool_t::current_pool->find(symbol))
out << '@';
out << symbol;
}
if (context.end_pos && this == context.op_to_find) {
*context.end_pos = out.tellp();
*context.end_pos -= 1;
}
return found;
}
void expr_t::op_t::dump(std::ostream& out, const int depth) const
{
out.setf(std::ios::left);
out.width((sizeof(void *) * 2) + 2);
out << this;
for (int i = 0; i < depth; i++)
out << " ";
switch (kind) {
case PLUG:
out << "PLUG";
break;
case VALUE:
out << "VALUE: ";
as_value().dump(out);
break;
case IDENT:
out << "IDENT: " << as_ident();
break;
case FUNCTION:
out << "FUNCTION";
break;
case SCOPE:
out << "SCOPE: ";
if (is_scope_unset())
out << "null";
else
out << as_scope().get();
break;
case O_DEFINE: out << "O_DEFINE"; break;
case O_LOOKUP: out << "O_LOOKUP"; break;
case O_LAMBDA: out << "O_LAMBDA"; break;
case O_CALL: out << "O_CALL"; break;
case O_MATCH: out << "O_MATCH"; break;
case O_NOT: out << "O_NOT"; break;
case O_NEG: out << "O_NEG"; break;
case O_ADD: out << "O_ADD"; break;
case O_SUB: out << "O_SUB"; break;
case O_MUL: out << "O_MUL"; break;
case O_DIV: out << "O_DIV"; break;
case O_EQ: out << "O_EQ"; break;
case O_LT: out << "O_LT"; break;
case O_LTE: out << "O_LTE"; break;
case O_GT: out << "O_GT"; break;
case O_GTE: out << "O_GTE"; break;
case O_AND: out << "O_AND"; break;
case O_OR: out << "O_OR"; break;
case O_QUERY: out << "O_QUERY"; break;
case O_COLON: out << "O_COLON"; break;
case O_CONS: out << "O_CONS"; break;
case O_SEQ: out << "O_SEQ"; break;
case LAST:
default:
assert(false);
break;
}
out << " (" << refc << ')' << std::endl;
// An identifier is a special non-terminal, in that its left() can
// hold the compiled definition of the identifier.
if (kind > TERMINALS || is_scope() || is_ident()) {
if (left()) {
left()->dump(out, depth + 1);
if (kind > UNARY_OPERATORS && has_right())
right()->dump(out, depth + 1);
}
else if (kind > UNARY_OPERATORS) {
assert(! has_right());
}
}
}
string op_context(const expr_t::ptr_op_t op,
const expr_t::ptr_op_t locus)
{
ostream_pos_type start_pos, end_pos;
expr_t::op_t::context_t context(op, locus, &start_pos, &end_pos);
std::ostringstream buf;
buf << " ";
if (op->print(buf, context)) {
buf << "\n";
for (int i = 0; i <= end_pos; i++) {
if (i > start_pos)
buf << "^";
else
buf << " ";
}
}
return buf.str();
}
} // namespace ledger