libeval_compiler.cpp

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/*
 * This file is part of libeval, a simple math expression evaluator
 *
 * Copyright (C) 2017 Michael Geselbracht, [email protected]
 * Copyright (C) 2019-2021 KiCad Developers, see AUTHORS.txt for contributors.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <https://www.gnu.org/licenses/>.
 */

#include <memory>
#include <set>
#include <vector>
#include <algorithm>

#include <string_utils.h>
#include <wx/log.h>

#ifdef DEBUG
#include <cstdarg>
#endif

#include <libeval_compiler/libeval_compiler.h>

/* The (generated) lemon parser is written in C.
 * In order to keep its symbol from the global namespace include the parser code with
 * a C++ namespace.
 */
namespace LIBEVAL
{

#ifdef __GNUC__
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-variable"
#pragma GCC diagnostic ignored "-Wsign-compare"
#endif

#include <libeval_compiler/grammar.c>
#include <libeval_compiler/grammar.h>

#ifdef __GNUC__
#pragma GCC diagnostic pop
#endif


#define libeval_dbg(level, fmt, ...) \
 wxLogTrace( "libeval_compiler", fmt, __VA_ARGS__ );


TREE_NODE* newNode( LIBEVAL::COMPILER* compiler, int op, const T_TOKEN_VALUE& value )
{
 auto t2 = new TREE_NODE();

 t2->valid = true;
 t2->value.str = value.str ? new wxString( *value.str ) : nullptr;
 t2->value.num = value.num;
 t2->value.idx = value.idx;
 t2->op = op;
 t2->leaf[0] = nullptr;
 t2->leaf[1] = nullptr;
 t2->isTerminal = false;
 t2->srcPos = compiler->GetSourcePos();
 t2->uop = nullptr;

 libeval_dbg(10, " ostr %p nstr %p nnode %p op %d", value.str, t2->value.str, t2, t2->op );

 if(t2->value.str)
 compiler->GcItem( t2->value.str );

 compiler->GcItem( t2 );

 return t2;
}


static const wxString formatOpName( int op )
{
 static const struct
 {
 int op;
 wxString mnemonic;
 }
 simpleOps[] =
 {
 { TR_OP_MUL, "MUL" }, { TR_OP_DIV, "DIV" }, { TR_OP_ADD, "ADD" },
 { TR_OP_SUB, "SUB" }, { TR_OP_LESS, "LESS" }, { TR_OP_GREATER, "GREATER" },
 { TR_OP_LESS_EQUAL, "LESS_EQUAL" }, { TR_OP_GREATER_EQUAL, "GREATER_EQUAL" },
 { TR_OP_EQUAL, "EQUAL" }, { TR_OP_NOT_EQUAL, "NEQUAL" }, { TR_OP_BOOL_AND, "AND" },
 { TR_OP_BOOL_OR, "OR" }, { TR_OP_BOOL_NOT, "NOT" }, { -1, "" }
 };

 for( int i = 0; simpleOps[i].op >= 0; i++ )
 {
 if( simpleOps[i].op == op )
 return simpleOps[i].mnemonic;
 }

 return "???";
}


bool VALUE::EqualTo( CONTEXT* aCtx, const VALUE* b ) const
{
 if( m_type == VT_UNDEFINED || b->m_type == VT_UNDEFINED )
 return false;

 if( m_type == VT_NUMERIC && b->m_type == VT_NUMERIC )
 {
 return m_valueDbl == b->m_valueDbl;
  }
 else if( m_type == VT_STRING && b->m_type == VT_STRING )
 {
 if( b->m_stringIsWildcard )
 return WildCompareString( b->m_valueStr, m_valueStr, false );
 else
 return !m_valueStr.CmpNoCase( b->m_valueStr );
 }

 return false;
}


bool VALUE::NotEqualTo( CONTEXT* aCtx, const VALUE* b ) const
{
 if( m_type == VT_UNDEFINED || b->m_type == VT_UNDEFINED )
 return false;

 return !EqualTo( aCtx, b );
}


wxString UOP::Format() const
{
 wxString str;

 switch( m_op )
 {
 case TR_UOP_PUSH_VAR:
 str = wxString::Format( "PUSH VAR [%p]", m_ref.get() );
 break;

 case TR_UOP_PUSH_VALUE:
 {
 if( !m_value )
 str = wxString::Format( "PUSH nullptr" );
 else if( m_value->GetType() == VT_NUMERIC )
 str = wxString::Format( "PUSH NUM [%.10f]", m_value->AsDouble() );
 else
 str = wxString::Format( "PUSH STR [%ls]", m_value->AsString() );
 }
 break;

 case TR_OP_METHOD_CALL:
 str = wxString::Format( "MCALL" );
 break;

 case TR_OP_FUNC_CALL:
 str = wxString::Format( "FCALL" );
 break;

 default:
 str = wxString::Format( "%s %d", formatOpName( m_op ).c_str(), m_op );
 break;
 }

 return str;
}


UCODE::~UCODE()
{
 for ( auto op : m_ucode )
 {
 delete op;
 }
}


wxString UCODE::Dump() const
{
 wxString rv;

 for( auto op : m_ucode )
 {
 rv += op->Format();
 rv += "\n";
 }

 return rv;
};


wxString TOKENIZER::GetChars( const std::function<bool( wxUniChar )>& cond ) const
{
 wxString rv;
 size_t p = m_pos;

 while( p < m_str.length() && cond( m_str[p] ) )
 {
 rv.append( 1, m_str[p] );
 p++;
 }

 return rv;
}

bool TOKENIZER::MatchAhead( const wxString& match,
 const std::function<bool( wxUniChar )>& stopCond ) const
{
 int remaining = (int) m_str.Length() - m_pos;

 if( remaining < (int) match.length() )
 return false;

 if( m_str.substr( m_pos, match.length() ) == match )
 return ( remaining == (int) match.length() || stopCond( m_str[m_pos + match.length()] ) );

 return false;
}


COMPILER::COMPILER() :
 m_lexerState( COMPILER::LS_DEFAULT )
{
 m_localeDecimalSeparator = '.';
 m_sourcePos = 0;
 m_parseFinished = false;
 m_unitResolver = std::make_unique<UNIT_RESOLVER>();
 m_parser = LIBEVAL::ParseAlloc( malloc );
 m_tree = nullptr;
 m_errorStatus.pendingError = false;
}


COMPILER::~COMPILER()
{
 LIBEVAL::ParseFree( m_parser, free );

 if( m_tree )
 {
 freeTree( m_tree );
 }

 // Allow explicit call to destructor
 m_parser = nullptr;

 Clear();
}


void COMPILER::Clear()
{
 //free( current.token );
 m_tokenizer.Clear();

 if( m_tree )
 {
 freeTree( m_tree );
 m_tree = nullptr;
 }

 m_tree = nullptr;

 for( auto tok : m_gcItems )
 delete tok;

 for( auto tok: m_gcStrings )
 delete tok;

 m_gcItems.clear();
 m_gcStrings.clear();
}


void COMPILER::parseError( const char* s )
{
 reportError( CST_PARSE, s );
}


void COMPILER::parseOk()
{
 m_parseFinished = true;
}


bool COMPILER::Compile( const wxString& aString, UCODE* aCode, CONTEXT* aPreflightContext )
{
 // Feed parser token after token until end of input.

 newString( aString );

 if( m_tree )
 {
 freeTree( m_tree );
 m_tree = nullptr;
 }

 m_tree = nullptr;
 m_parseFinished = false;
 T_TOKEN tok( defaultToken );

 libeval_dbg(0, "str: '%s' empty: %d\n", aString.c_str(), !!aString.empty() );

 if( aString.empty() )
 {
 m_parseFinished = true;
 return generateUCode( aCode, aPreflightContext );
 }

 do
 {
 m_sourcePos = m_tokenizer.GetPos();

 tok = getToken();

 if( tok.value.str )
 GcItem( tok.value.str );

 libeval_dbg(10, "parse: tok %d valstr %p\n", tok.token, tok.value.str );
 Parse( m_parser, tok.token, tok, this );

 if ( m_errorStatus.pendingError )
 return false;

 if( m_parseFinished || tok.token == G_ENDS )
 {
 // Reset parser by passing zero as token ID, value is ignored.
 Parse( m_parser, 0, tok, this );
 break;
 }
 } while( tok.token );

 return generateUCode( aCode, aPreflightContext );
}


void COMPILER::newString( const wxString& aString )
{
 Clear();

 m_lexerState = LS_DEFAULT;
 m_tokenizer.Restart( aString );
 m_parseFinished = false;
}

T_TOKEN COMPILER::getToken()
{
 T_TOKEN rv;
 rv.value.str = nullptr;

 bool done = false;

 do
 {
 switch( m_lexerState )
 {
 case LS_DEFAULT:
 done = lexDefault( rv );
 break;
 case LS_STRING:
 done = lexString( rv );
 break;
 }
 } while( !done );

 return rv;
}


bool COMPILER::lexString( T_TOKEN& aToken )
{
 wxString str = m_tokenizer.GetChars( []( int c ) -> bool { return c != '\''; } );

 aToken.token = G_STRING;
 aToken.value.str = new wxString( str );

 m_tokenizer.NextChar( str.length() + 1 );
 m_lexerState = LS_DEFAULT;
 return true;
}


int COMPILER::resolveUnits()
{
 int unitId = 0;

 for( const wxString& unitName : m_unitResolver->GetSupportedUnits() )
 {
 if( m_tokenizer.MatchAhead( unitName, []( int c ) -> bool { return !isalnum( c ); } ) )
 {
 libeval_dbg(10, "Match unit '%s'\n", unitName.c_str() );
 m_tokenizer.NextChar( unitName.length() );
 return unitId;
 }

 unitId++;
 }

 return -1;
}


bool COMPILER::lexDefault( T_TOKEN& aToken )
{
 T_TOKEN retval;
 wxString current;
 int convertFrom;
 wxString msg;

 retval.value.str = nullptr;
 retval.value.num = 0.0;
 retval.value.idx = -1;
 retval.token = G_ENDS;

 if( m_tokenizer.Done() )
 {
 aToken = retval;
 return true;
 }

 auto isDecimalSeparator =
 [&]( wxUniChar ch ) -> bool
 {
 return ( ch == m_localeDecimalSeparator || ch == '.' || ch == ',' );
 };

 // Lambda: get value as string, store into clToken.token and update current index.
 auto extractNumber =
 [&]()
 {
 bool haveSeparator = false;
 wxUniChar ch = m_tokenizer.GetChar();

 do
 {
 if( isDecimalSeparator( ch ) && haveSeparator )
 break;

 current.append( 1, ch );

 if( isDecimalSeparator( ch ) )
 haveSeparator = true;

 m_tokenizer.NextChar();
 ch = m_tokenizer.GetChar();
 } while( isdigit( ch ) || isDecimalSeparator( ch ) );

 // Ensure that the systems decimal separator is used
 for( int i = current.length(); i; i-- )
 {
 if( isDecimalSeparator( current[i - 1] ) )
 current[i - 1] = m_localeDecimalSeparator;
 }
 };


 int ch;

 // Start processing of first/next token: Remove whitespace
 for( ;; )
 {
 ch = m_tokenizer.GetChar();

 if( ch == ' ' )
 m_tokenizer.NextChar();
 else
 break;
 }

 libeval_dbg(10, "LEX ch '%c' pos %lu\n", ch, (unsigned long)m_tokenizer.GetPos() );

 if( ch == 0 )
 {
 /* End of input */
 }
 else if( isdigit( ch ) )
 {
 // VALUE
 extractNumber();
 retval.token = G_VALUE;
 retval.value.str = new wxString( current );
 }
 else if( ( convertFrom = resolveUnits() ) >= 0 )
 {
 // UNIT
 // Units are appended to a VALUE.
 // Determine factor to default unit if unit for value is given.
 // Example: Default is mm, unit is inch: factor is 25.4
 // The factor is assigned to the terminal UNIT. The actual
 // conversion is done within a parser action.
 retval.token = G_UNIT;
 retval.value.idx = convertFrom;
 }
 else if( ch == '\'' ) // string literal
 {
 m_lexerState = LS_STRING;
 m_tokenizer.NextChar();
 return false;
 }
 else if( isalpha( ch ) || ch == '_' )
 {
 current = m_tokenizer.GetChars( []( int c ) -> bool { return isalnum( c ) || c == '_'; } );
 retval.token = G_IDENTIFIER;
 retval.value.str = new wxString( current );
 m_tokenizer.NextChar( current.length() );
 }
 else if( m_tokenizer.MatchAhead( "==", []( int c ) -> bool { return c != '='; } ) )
 {
 retval.token = G_EQUAL;
 m_tokenizer.NextChar( 2 );
 }
 else if( m_tokenizer.MatchAhead( "!=", []( int c ) -> bool { return c != '='; } ) )
 {
 retval.token = G_NOT_EQUAL;
 m_tokenizer.NextChar( 2 );
 }
 else if( m_tokenizer.MatchAhead( "<=", []( int c ) -> bool { return c != '='; } ) )
 {
 retval.token = G_LESS_EQUAL_THAN;
 m_tokenizer.NextChar( 2 );
 }
 else if( m_tokenizer.MatchAhead( ">=", []( int c ) -> bool { return c != '='; } ) )
 {
 retval.token = G_GREATER_EQUAL_THAN;
 m_tokenizer.NextChar( 2 );
 }
 else if( m_tokenizer.MatchAhead( "&&", []( int c ) -> bool { return c != '&'; } ) )
 {
 retval.token = G_BOOL_AND;
 m_tokenizer.NextChar( 2 );
 }
 else if( m_tokenizer.MatchAhead( "||", []( int c ) -> bool { return c != '|'; } ) )
 {
 retval.token = G_BOOL_OR;
 m_tokenizer.NextChar( 2 );
 }
 else
 {
 // Single char tokens
 switch( ch )
 {
 case '+': retval.token = G_PLUS; break;
 case '!': retval.token = G_BOOL_NOT; break;
 case '-': retval.token = G_MINUS; break;
 case '*': retval.token = G_MULT; break;
 case '/': retval.token = G_DIVIDE; break;
 case '<': retval.token = G_LESS_THAN; break;
 case '>': retval.token = G_GREATER_THAN; break;
 case '(': retval.token = G_PARENL; break;
 case ')': retval.token = G_PARENR; break;
 case ';': retval.token = G_SEMCOL; break;
 case '.': retval.token = G_STRUCT_REF; break;
 case ',': retval.token = G_COMMA; break;

 default:
 reportError( CST_PARSE, wxString::Format( _( "Unrecognized character '%c'" ),
 (char) ch ) );
 break;
 }

 m_tokenizer.NextChar();
 }

 aToken = retval;
 return true;
}


const wxString formatNode( TREE_NODE* node )
{
 return node->value.str ? *(node->value.str) : "";
}


void dumpNode( wxString& buf, TREE_NODE* tok, int depth = 0 )
{
 wxString str;

 if( !tok )
 return;

 str.Printf( "\n[%p L0:%-20p L1:%-20p] ", tok, tok->leaf[0], tok->leaf[1] );
 buf += str;

 for( int i = 0; i < 2 * depth; i++ )
 buf += " ";

 if( tok->op & TR_OP_BINARY_MASK )
 {
 buf += formatOpName( tok->op );
 dumpNode( buf, tok->leaf[0], depth + 1 );
 dumpNode( buf, tok->leaf[1], depth + 1 );
 }

 switch( tok->op )
 {
 case TR_NUMBER:
 buf += "NUMERIC: ";
 buf += formatNode( tok );

 if( tok->leaf[0] )
 dumpNode( buf, tok->leaf[0], depth + 1 );

 break;

 case TR_ARG_LIST:
 buf += "ARG_LIST: ";
 buf += formatNode( tok );

 if( tok->leaf[0] )
 dumpNode( buf, tok->leaf[0], depth + 1 );
 if( tok->leaf[1] )
 dumpNode( buf, tok->leaf[1], depth + 1 );

 break;

 case TR_STRING:
 buf += "STRING: ";
 buf += formatNode( tok );
 break;

 case TR_IDENTIFIER:
 buf += "ID: ";
 buf += formatNode( tok );
 break;

 case TR_STRUCT_REF:
 buf += "SREF: ";
 dumpNode( buf, tok->leaf[0], depth + 1 );
 dumpNode( buf, tok->leaf[1], depth + 1 );
 break;

 case TR_OP_FUNC_CALL:
 buf += "CALL '";
 buf += *tok->leaf[0]->value.str;
 buf += "': ";
 dumpNode( buf, tok->leaf[1], depth + 1 );
 break;

 case TR_UNIT:
 str.Printf( "UNIT: %d ", tok->value.idx );
 buf += str;
 break;
 }
}


void CONTEXT::ReportError( const wxString& aErrorMsg )
{
 if( m_errorCallback )
 m_errorCallback( aErrorMsg, -1 );
}


void COMPILER::reportError( COMPILATION_STAGE stage, const wxString& aErrorMsg, int aPos )
{
 if( aPos == -1 )
 aPos = m_sourcePos;

 m_errorStatus.pendingError = true;
 m_errorStatus.stage = stage;
 m_errorStatus.message = aErrorMsg;
 m_errorStatus.srcPos = aPos;

 if( m_errorCallback )
 m_errorCallback( aErrorMsg, aPos );
}


void COMPILER::setRoot( TREE_NODE *root )
{
 m_tree = root;
}


void COMPILER::freeTree( LIBEVAL::TREE_NODE *tree )
{
 if ( tree->leaf[0] )
 freeTree( tree->leaf[0] );

 if ( tree->leaf[1] )
 freeTree( tree->leaf[1] );

 delete tree->uop;
}


void TREE_NODE::SetUop( int aOp, double aValue )
{
 delete uop;

 std::unique_ptr<VALUE> val = std::make_unique<VALUE>( aValue );
 uop = new UOP( aOp, std::move( val ) );
}


void TREE_NODE::SetUop( int aOp, const wxString& aValue, bool aStringIsWildcard )
{
 delete uop;

 std::unique_ptr<VALUE> val = std::make_unique<VALUE>( aValue, aStringIsWildcard );
 uop = new UOP( aOp, std::move( val ) );
}


void TREE_NODE::SetUop( int aOp, std::unique_ptr<VAR_REF> aRef )
{
 delete uop;

 uop = new UOP( aOp, std::move( aRef ) );
}


void TREE_NODE::SetUop( int aOp, FUNC_CALL_REF aFunc, std::unique_ptr<VAR_REF> aRef )
{
 delete uop;

 uop = new UOP( aOp, std::move( aFunc ), std::move( aRef ) );
}


static void prepareTree( LIBEVAL::TREE_NODE *node )
{
 node->isVisited = false;

 // fixme: for reasons I don't understand the lemon parser isn't initializing the
 // leaf node pointers of function name nodes. -JY
 if( node->op == TR_OP_FUNC_CALL && node->leaf[0] )
 {
 node->leaf[0]->leaf[0] = nullptr;
 node->leaf[0]->leaf[1] = nullptr;
 }

 if ( node->leaf[0] )
 prepareTree( node->leaf[0] );

 if ( node->leaf[1] )
 prepareTree( node->leaf[1] );
}

static std::vector<TREE_NODE*> squashParamList( TREE_NODE* root )
{
 std::vector<TREE_NODE*> args;

 if( !root )
 {
 return args;
 }

 if( root->op != TR_ARG_LIST && root->op != TR_NULL )
 {
 args.push_back( root );
 }
 else
 {
 TREE_NODE *n = root;
 do
 {
 if( n->leaf[1] )
 args.push_back(n->leaf[1]);

 n = n->leaf[0];
 } while ( n && n->op == TR_ARG_LIST );

 if( n )
 {
 args.push_back( n );
 }
 }

 std::reverse( args.begin(), args.end() );

 for( size_t i = 0; i < args.size(); i++ )
 libeval_dbg( 10, "squash arg%d: %s\n", int( i ), *args[i]->value.str );

 return args;
}


bool COMPILER::generateUCode( UCODE* aCode, CONTEXT* aPreflightContext )
{
 std::vector<TREE_NODE*> stack;
 wxString msg;

 if( !m_tree )
 {
 std::unique_ptr<VALUE> val = std::make_unique<VALUE>( 1.0 );
 // Empty expression returns true
 aCode->AddOp( new UOP( TR_UOP_PUSH_VALUE, std::move(val) ) );
 return true;
 }

 prepareTree( m_tree );

 stack.push_back( m_tree );

 wxString dump;

 dumpNode( dump, m_tree, 0 );
 libeval_dbg( 3, "Tree dump:\n%s\n\n", (const char*) dump.c_str() );

 while( !stack.empty() )
 {
 TREE_NODE* node = stack.back();

 libeval_dbg( 4, "process node %p [op %d] [stack %lu]\n",
 node, node->op, (unsigned long)stack.size() );

 // process terminal nodes first
 switch( node->op )
 {
 case TR_OP_FUNC_CALL:
 // Function call's uop was generated inside TR_STRUCT_REF
 if( !node->uop )
 {
 reportError( CST_CODEGEN, _( "Unknown parent of function parameters" ),
 node->srcPos );
 }

 node->isTerminal = true;
 break;

 case TR_STRUCT_REF:
 {
 // leaf[0]: object
 // leaf[1]: field (TR_IDENTIFIER) or TR_OP_FUNC_CALL

 if( node->leaf[0]->op != TR_IDENTIFIER )
 {
 int pos = node->leaf[0]->srcPos;

 if( node->leaf[0]->value.str )
 pos -= static_cast<int>( node->leaf[0]->value.str->length() );

 reportError( CST_CODEGEN, _( "Unknown parent of property" ), pos );

 node->leaf[0]->isVisited = true;
 node->leaf[1]->isVisited = true;

 node->SetUop( TR_UOP_PUSH_VALUE, 0.0 );
 node->isTerminal = true;
 break;
 }

 switch( node->leaf[1]->op )
 {
 case TR_IDENTIFIER:
 {
 // leaf[0]: object
 // leaf[1]: field

 wxString itemName = *node->leaf[0]->value.str;
 wxString propName = *node->leaf[1]->value.str;
 std::unique_ptr<VAR_REF> vref = aCode->CreateVarRef( itemName, propName );

 if( !vref )
 {
 msg.Printf( _( "Unrecognized item '%s'" ), itemName );
 reportError( CST_CODEGEN, msg,
 node->leaf[0]->srcPos - (int) itemName.length() );
 }
 else if( vref->GetType() == VT_PARSE_ERROR )
 {
 msg.Printf( _( "Unrecognized property '%s'" ), propName );
 reportError( CST_CODEGEN, msg,
 node->leaf[1]->srcPos - (int) propName.length() );
 }

 node->leaf[0]->isVisited = true;
 node->leaf[1]->isVisited = true;

 node->SetUop( TR_UOP_PUSH_VAR, std::move( vref ) );
 node->isTerminal = true;
 break;
 }
 case TR_OP_FUNC_CALL:
 {
 // leaf[0]: object
 // leaf[1]: TR_OP_FUNC_CALL
 // leaf[0]: function name
 // leaf[1]: parameter

 wxString itemName = *node->leaf[0]->value.str;
 std::unique_ptr<VAR_REF> vref = aCode->CreateVarRef( itemName, "" );

 if( !vref )
 {
 msg.Printf( _( "Unrecognized item '%s'" ), itemName );
 reportError( CST_CODEGEN, msg,
 node->leaf[0]->srcPos - (int) itemName.length() );
 }

 wxString functionName = *node->leaf[1]->leaf[0]->value.str;
 auto func = aCode->CreateFuncCall( functionName );
 std::vector<TREE_NODE*> params = squashParamList( node->leaf[1]->leaf[1] );

 libeval_dbg( 10, "emit func call: %s\n", functionName );

 if( !func )
 {
 msg.Printf( _( "Unrecognized function '%s'" ), functionName );
 reportError( CST_CODEGEN, msg, node->leaf[0]->srcPos + 1 );
 }

 if( func )
 {
 // Preflight the function call

 for( TREE_NODE* pnode : params )
 {
 VALUE* param = aPreflightContext->AllocValue();
 param->Set( *pnode->value.str );
 aPreflightContext->Push( param );
 }

 aPreflightContext->SetErrorCallback(
 [&]( const wxString& aMessage, int aOffset )
 {
 size_t loc = node->leaf[1]->leaf[1]->srcPos;
 reportError( CST_CODEGEN, aMessage, (int) loc - 1 );
 } );

 try
 {
 func( aPreflightContext, vref.get() );
 aPreflightContext->Pop(); // return value
 }
 catch( ... )
 {
 }
 }

 node->leaf[0]->isVisited = true;
 node->leaf[1]->isVisited = true;
 node->leaf[1]->leaf[0]->isVisited = true;
 node->leaf[1]->leaf[1]->isVisited = true;

 // Our non-terminal-node stacking algorithm can't handle doubly-nested
 // structures so we need to pop a level by replacing the TR_STRUCT_REF with
 // a TR_OP_FUNC_CALL and its function parameter
 stack.pop_back();
 stack.push_back( node->leaf[1] );

 for( TREE_NODE* pnode : params )
 stack.push_back( pnode );

 node->leaf[1]->SetUop( TR_OP_METHOD_CALL, func, std::move( vref ) );
 node->isTerminal = false;
 break;
 }

 default:
 // leaf[0]: object
 // leaf[1]: malformed syntax

 wxString itemName = *node->leaf[0]->value.str;
 wxString propName = *node->leaf[1]->value.str;
 std::unique_ptr<VAR_REF> vref = aCode->CreateVarRef( itemName, propName );

 if( !vref )
 {
 msg.Printf( _( "Unrecognized item '%s'" ), itemName );
 reportError( CST_CODEGEN, msg,
 node->leaf[0]->srcPos - (int) itemName.length() );
 }

 msg.Printf( _( "Unrecognized property '%s'" ), propName );
 reportError( CST_CODEGEN, msg, node->leaf[0]->srcPos + 1 );

 node->leaf[0]->isVisited = true;
 node->leaf[1]->isVisited = true;

 node->SetUop( TR_UOP_PUSH_VALUE, 0.0 );
 node->isTerminal = true;
 break;
 }

 break;
 }

 case TR_NUMBER:
 {
 TREE_NODE* son = node->leaf[0];
 double value;

 if( !node->value.str )
 {
 value = 0.0;
 }
 else if( son && son->op == TR_UNIT )
 {
 int units = son->value.idx;
 value = m_unitResolver->Convert( *node->value.str, units );
 son->isVisited = true;
 }
 else
 {
 msg.Printf( _( "Missing units for '%s'| (%s)" ),
 *node->value.str,
 m_unitResolver->GetSupportedUnitsMessage() );
 reportError( CST_CODEGEN, msg, node->srcPos );

 value = DoubleValueFromString( EDA_UNITS::UNSCALED, *node->value.str );
 }

 node->SetUop( TR_UOP_PUSH_VALUE, value );
 node->isTerminal = true;
 break;
 }

 case TR_STRING:
 {
 wxString str = *node->value.str;
 bool isWildcard = str.Contains("?") || str.Contains("*");
 node->SetUop( TR_UOP_PUSH_VALUE, str, isWildcard );
 node->isTerminal = true;
 break;
 }

 case TR_IDENTIFIER:
 {
 std::unique_ptr<VAR_REF> vref = aCode->CreateVarRef( *node->value.str, "" );

 if( !vref )
 {
 msg.Printf( _( "Unrecognized item '%s'" ), *node->value.str );
 reportError( CST_CODEGEN, msg, node->srcPos - (int) node->value.str->length() );
 }

 node->SetUop( TR_UOP_PUSH_VALUE, std::move( vref ) );
 node->isTerminal = true;
 break;
 }

 default:
 node->SetUop( node->op );
 node->isTerminal = ( !node->leaf[0] || node->leaf[0]->isVisited )
 && ( !node->leaf[1] || node->leaf[1]->isVisited );
 break;
 }

 if( !node->isTerminal )
 {
 if( node->leaf[0] && !node->leaf[0]->isVisited )
 {
 stack.push_back( node->leaf[0] );
 node->leaf[0]->isVisited = true;
 continue;
 }
 else if( node->leaf[1] && !node->leaf[1]->isVisited )
 {
 stack.push_back( node->leaf[1] );
 node->leaf[1]->isVisited = true;
 }

 continue;
 }

 node->isVisited = true;

 if( node->uop )
 {
 aCode->AddOp( node->uop );
 node->uop = nullptr;
 }

 stack.pop_back();
 }

 libeval_dbg(2,"dump: \n%s\n", aCode->Dump().c_str() );

 return true;
}


void UOP::Exec( CONTEXT* ctx )
{
 switch( m_op )
 {
 case TR_UOP_PUSH_VAR:
 {
 VALUE* value = ctx->AllocValue();

 if( m_ref )
 value->Set( m_ref->GetValue( ctx ) );

 ctx->Push( value );
 }
 break;

 case TR_UOP_PUSH_VALUE:
 ctx->Push( m_value.get() );
 return;

 case TR_OP_METHOD_CALL:
 m_func( ctx, m_ref.get() );
 return;

 default:
 break;
 }

 if( m_op & TR_OP_BINARY_MASK )
 {
 LIBEVAL::VALUE* arg2 = ctx->Pop();
 LIBEVAL::VALUE* arg1 = ctx->Pop();
 double arg2Value = arg2 ? arg2->AsDouble() : 0.0;
 double arg1Value = arg1 ? arg1->AsDouble() : 0.0;
 double result;

 if( ctx->HasErrorCallback() )
 {
 if( arg1 && arg1->GetType() == VT_STRING && arg2 && arg2->GetType() == VT_NUMERIC )
 {
 ctx->ReportError( wxString::Format( _( "Type mismatch between '%s' and %lf" ),
 arg1->AsString(),
 arg2->AsDouble() ) );
 }
 else if( arg1 && arg1->GetType() == VT_NUMERIC && arg2 && arg2->GetType() == VT_STRING )
 {
 ctx->ReportError( wxString::Format( _( "Type mismatch between %lf and '%s'" ),
 arg1->AsDouble(),
 arg2->AsString() ) );
 }
 }

 switch( m_op )
 {
 case TR_OP_ADD:
 result = arg1Value + arg2Value;
 break;
 case TR_OP_SUB:
 result = arg1Value - arg2Value;
 break;
 case TR_OP_MUL:
 result = arg1Value * arg2Value;
 break;
 case TR_OP_DIV:
 result = arg1Value / arg2Value;
 break;
 case TR_OP_LESS_EQUAL:
 result = arg1Value <= arg2Value ? 1 : 0;
 break;
 case TR_OP_GREATER_EQUAL:
 result = arg1Value >= arg2Value ? 1 : 0;
 break;
 case TR_OP_LESS:
 result = arg1Value < arg2Value ? 1 : 0;
 break;
 case TR_OP_GREATER:
 result = arg1Value > arg2Value ? 1 : 0;
 break;
 case TR_OP_EQUAL:
 result = arg1 && arg2 && arg1->EqualTo( ctx, arg2 ) ? 1 : 0;
 break;
 case TR_OP_NOT_EQUAL:
 result = arg1 && arg2 && arg1->NotEqualTo( ctx, arg2 ) ? 1 : 0;
 break;
 case TR_OP_BOOL_AND:
 result = arg1Value != 0.0 && arg2Value != 0.0 ? 1 : 0;
 break;
 case TR_OP_BOOL_OR:
 result = arg1Value != 0.0 || arg2Value != 0.0 ? 1 : 0;
 break;
 default:
 result = 0.0;
 break;
 }

 auto rp = ctx->AllocValue();
 rp->Set( result );
 ctx->Push( rp );
 return;
 }
 else if( m_op & TR_OP_UNARY_MASK )
 {
 LIBEVAL::VALUE* arg1 = ctx->Pop();
 double arg1Value = arg1 ? arg1->AsDouble() : 0.0;
 double result;

 switch( m_op )
 {
 case TR_OP_BOOL_NOT:
 result = arg1Value != 0.0 ? 0 : 1;
 break;
 default:
 result = 0.0;
 break;
 }

 auto rp = ctx->AllocValue();
 rp->Set( result );
 ctx->Push( rp );
 return;
 }
}


VALUE* UCODE::Run( CONTEXT* ctx )
{
 static VALUE g_false( 0 );

 try
 {
 for( UOP* op : m_ucode )
 op->Exec( ctx );
 }
 catch(...)
 {
 // rules which fail outright should not be fired
 return &g_false;
 }

 if( ctx->SP() == 1 )
 {
 return ctx->Pop();
 }
 else
 {
 // If stack is corrupted after execution it suggests a problem with the compiler, not
 // the rule....

 // do not use "assert"; it crashes outright on OSX
 wxASSERT( ctx->SP() == 1 );

 // non-well-formed rules should not be fired on a release build
 return &g_false;
 }
}


} // namespace LIBEVAL