[Boost-commit] svn:boost r61391 - in trunk/libs/spirit/example/scheme: example example/scheme example/sexpr input scheme test/scheme

Subject: [Boost-commit] svn:boost r61391 - in trunk/libs/spirit/example/scheme: example example/scheme example/sexpr input scheme test/scheme
From: joel_at_[hidden]
Date: 2010-04-18 22:31:11

Author: djowel
Date: 2010-04-18 22:31:08 EDT (Sun, 18 Apr 2010)
New Revision: 61391
URL: http://svn.boost.org/trac/boost/changeset/61391

Log:
refining the error checking
Added:
   trunk/libs/spirit/example/scheme/example/scheme/scheme_error_test.cpp   (contents, props changed)
   trunk/libs/spirit/example/scheme/test/scheme/scheme_error.scm   (contents, props changed)
Text files modified: 
   trunk/libs/spirit/example/scheme/example/Jamfile              |     1                                         
   trunk/libs/spirit/example/scheme/example/sexpr/out.txt        |     2                                         
   trunk/libs/spirit/example/scheme/example/sexpr/sexpr_test.txt |     2                                         
   trunk/libs/spirit/example/scheme/input/parse_sexpr_impl.hpp   |     8 +                                       
   trunk/libs/spirit/example/scheme/input/sexpr.hpp              |     2                                         
   trunk/libs/spirit/example/scheme/scheme/compiler.hpp          |   238 ++++++++++++++++++++++++--------------- 
   trunk/libs/spirit/example/scheme/scheme/interpreter.hpp       |    39 ++++++                                  
   7 files changed, 194 insertions(+), 98 deletions(-)

Modified: trunk/libs/spirit/example/scheme/example/Jamfile
==============================================================================
--- trunk/libs/spirit/example/scheme/example/Jamfile	(original)
+++ trunk/libs/spirit/example/scheme/example/Jamfile	2010-04-18 22:31:08 EDT (Sun, 18 Apr 2010)
@@ -31,6 +31,7 @@
 exe factorial1 : scheme/factorial1.cpp ;
 exe factorial2 : scheme/factorial2.cpp ;
 
+exe scheme_error_test : scheme/scheme_error_test.cpp ;
 
 
 

Added: trunk/libs/spirit/example/scheme/example/scheme/scheme_error_test.cpp
==============================================================================
--- (empty file)
+++ trunk/libs/spirit/example/scheme/example/scheme/scheme_error_test.cpp	2010-04-18 22:31:08 EDT (Sun, 18 Apr 2010)
@@ -0,0 +1,47 @@
+/*=============================================================================
+    Copyright (c) 2001-2010 Joel de Guzman
+
+    Distributed under the Boost Software License, Version 1.0. (See accompanying
+    file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+=============================================================================*/
+#include <boost/config/warning_disable.hpp>
+
+#include <input/sexpr.hpp>
+#include <input/parse_sexpr_impl.hpp>
+#include <scheme/compiler.hpp>
+#include <utree/io.hpp>
+#include <fstream>
+
+///////////////////////////////////////////////////////////////////////////////
+//  Main program
+///////////////////////////////////////////////////////////////////////////////
+int main(int argc, char **argv)
+{
+    char const* filename = filename = argv[1];
+    std::ifstream in(filename, std::ios_base::in);
+
+    if (!in)
+    {
+        std::cerr << "scheme_error.scm not found" << std::endl;
+        return -1;
+    }
+
+    // Ignore the BOM marking the beginning of a UTF-8 file in Windows
+    char c = in.peek();
+    if (c == '\xef')
+    {
+        char s[3];
+        in >> s[0] >> s[1] >> s[2];
+        s[3] = '\0';
+        if (s != std::string("\xef\xbb\xbf"))
+        {
+            std::cerr << "unexpected characters in file" << std::endl;
+            return -1;
+        }
+    }
+
+    scheme::interpreter factorial(in, filename);
+    return 0;
+}
+
+

Modified: trunk/libs/spirit/example/scheme/example/sexpr/out.txt
==============================================================================
--- trunk/libs/spirit/example/scheme/example/sexpr/out.txt	(original)
+++ trunk/libs/spirit/example/scheme/example/sexpr/out.txt	2010-04-18 22:31:08 EDT (Sun, 18 Apr 2010)
@@ -1,2 +1,2 @@
-success: (123.45 true false 255 63 "this is a € string" "Τη γλώσσα μου έδωσαν ελληνική" b0123456789abcdef123456789abcdef (92 ("another string" apple Sîne)))
+success: (123.45 true false 255 63 "this is a € string" "Τη γλώσσα μου έδωσαν ελληνική" #0123456789abcdef123456789abcdef# (92 ("another string" apple Sîne)))
 

Modified: trunk/libs/spirit/example/scheme/example/sexpr/sexpr_test.txt
==============================================================================
--- trunk/libs/spirit/example/scheme/example/sexpr/sexpr_test.txt	(original)
+++ trunk/libs/spirit/example/scheme/example/sexpr/sexpr_test.txt	2010-04-18 22:31:08 EDT (Sun, 18 Apr 2010)
@@ -6,7 +6,7 @@
     077
     "this is a \u20AC string"           ; A UTF-8 string
     "Τη γλώσσα μου έδωσαν ελληνική"     ; Another UTF-8 string
-	b0123456789ABCDEF0123456789abcdef	; A binary stream
+	#0123456789ABCDEF0123456789abcdef#  ; A binary stream
     (
         92 ("another string" apple Sîne)
     )

Modified: trunk/libs/spirit/example/scheme/input/parse_sexpr_impl.hpp
==============================================================================
--- trunk/libs/spirit/example/scheme/input/parse_sexpr_impl.hpp	(original)
+++ trunk/libs/spirit/example/scheme/input/parse_sexpr_impl.hpp	2010-04-18 22:31:08 EDT (Sun, 18 Apr 2010)
@@ -69,7 +69,9 @@
         scheme::input::sexpr_white_space<iterator_type> ws;
 
         using boost::spirit::qi::phrase_parse;
-        return phrase_parse(first, last, +p, ws, result);
+        bool ok = phrase_parse(first, last, +p, ws, result);
+        result.tag(1); // line
+        return ok;
     }
 
     ///////////////////////////////////////////////////////////////////////////
@@ -112,7 +114,9 @@
         iterator_type last(rng.end());
 
         using boost::spirit::qi::phrase_parse;
-        return phrase_parse(first, last, +p, ws, result);
+        bool ok = phrase_parse(first, last, +p, ws, result);
+        result.tag(1); // line
+        return ok;
     }
 
     ///////////////////////////////////////////////////////////////////////////

Modified: trunk/libs/spirit/example/scheme/input/sexpr.hpp
==============================================================================
--- trunk/libs/spirit/example/scheme/input/sexpr.hpp	(original)
+++ trunk/libs/spirit/example/scheme/input/sexpr.hpp	2010-04-18 22:31:08 EDT (Sun, 18 Apr 2010)
@@ -119,7 +119,7 @@
                     | int_
                     ;
 
-            byte_str = lexeme[no_case['b'] > +hex2];
+            byte_str = lexeme['#' > +hex2 > '#'];
 
             start.name("sexpr");
             start.name("sexpr");

Modified: trunk/libs/spirit/example/scheme/scheme/compiler.hpp
==============================================================================
--- trunk/libs/spirit/example/scheme/scheme/compiler.hpp	(original)
+++ trunk/libs/spirit/example/scheme/scheme/compiler.hpp	2010-04-18 22:31:08 EDT (Sun, 18 Apr 2010)
@@ -23,27 +23,43 @@
 ///////////////////////////////////////////////////////////////////////////////
     struct scheme_exception : std::exception {};
 
-    struct identifier_not_found : scheme_exception
+    struct compilation_error : std::exception
     {
         virtual const char* what() const throw()
         {
-            return "scheme: Identifier not found";
+            return "scheme: Compilation error";
         }
     };
 
-    struct duplicate_identifier : scheme_exception
+    struct identifier_expected : scheme_exception
     {
         virtual const char* what() const throw()
         {
-            return "scheme: Duplicate identifier";
+            return "scheme: Identifier expected";
+        }
+    };
+
+    struct identifier_not_found : scheme_exception
+    {
+        std::string msg;
+        identifier_not_found(std::string const& id)
+          : msg("scheme: Identifier (" + id + ") not found") {}
+
+        virtual const char* what() const throw()
+        {
+            return msg.c_str();;
         }
     };
 
-    struct unknown_expression : scheme_exception
+    struct duplicate_identifier : scheme_exception
     {
+        std::string msg;
+        duplicate_identifier(std::string const& id)
+          : msg("scheme: Duplicate identifier (" + id + ')') {}
+
         virtual const char* what() const throw()
         {
-            return "scheme: Unknown_expression";
+            return "scheme: Duplicate identifier";
         }
     };
 
@@ -71,7 +87,7 @@
         void define(std::string const& name, Function const& f, int arity)
         {
             if (definitions.find(name) != definitions.end())
-                throw duplicate_identifier();
+                throw duplicate_identifier(name);
             definitions[name] = std::make_pair(compiled_function(f), arity);
         }
 
@@ -87,6 +103,16 @@
             return std::make_pair((compiled_function*)0, 0);
         }
 
+        void undefine(std::string const& name)
+        {
+            definitions.erase(name);
+        }
+
+        bool defined(std::string const& name)
+        {
+            return definitions.find(name) != definitions.end();
+        }
+
         environment* parent() const { return outer; }
 
     private:
@@ -160,7 +186,7 @@
                 actor_list flist;
                 return (*r.first)(flist);
             }
-            throw identifier_not_found();
+            throw identifier_not_found(name);
             return function();
         }
 
@@ -179,109 +205,111 @@
             std::vector<std::string> const& args,
             utree const& body) const
         {
-            fragments.push_back(function());
-            function& f = fragments.back();
-            env.define(name, external_function(f), args.size());
-            f = make_lambda(args, body);
-            return f;
+            try
+            {
+                if (env.defined(name))
+                    throw duplicate_identifier(name);
+                fragments.push_back(function());
+                function& f = fragments.back();
+                env.define(name, external_function(f), args.size());
+                f = make_lambda(args, body);
+                return f;
+            }
+            catch (compilation_error const&)
+            {
+                env.undefine(name);
+                throw;
+            }
         }
 
         template <typename Iterator>
         function operator()(boost::iterator_range<Iterator> const& range) const
         {
-            try
-            {
-                std::string name(get_symbol(*range.begin()));
+            std::string name(get_symbol(*range.begin()));
 
-                if (name == "define")
-                {
-                    std::string fname;
-                    std::vector<std::string> args;
-
-                    Iterator i = range.begin(); ++i;
-                    if (i->which() == utree_type::list_type)
-                    {
-                        // (define (f x) ...body...)
-                        utree const& decl = *i++;
-                        Iterator di = decl.begin();
-                        fname = get_symbol(*di++);
-                        while (di != decl.end())
-                            args.push_back(get_symbol(*di++));
-                    }
-                    else
-                    {
-                        // (define f ...body...)
-                        fname = get_symbol(*i++);
-
-                        // (define f (lambda (x) ...body...))
-                        if (i->which() == utree_type::list_type
-                            && get_symbol((*i)[0]) == "lambda")
-                        {
-                            utree const& arg_names = (*i)[1];
-                            Iterator ai = arg_names.begin();
-                            while (ai != arg_names.end())
-                                args.push_back(get_symbol(*ai++));
-                        }
-                    }
-
-                    return define_function(fname, args, *i);
-                }
+            if (name == "define")
+            {
+                std::string fname;
+                std::vector<std::string> args;
 
-                if (name == "lambda")
+                Iterator i = range.begin(); ++i;
+                if (i->which() == utree_type::list_type)
                 {
-                    // (lambda (x) ...body...)
-                    Iterator i = range.begin(); ++i;
-                    utree const& arg_names = *i++;
-                    Iterator ai = arg_names.begin();
-                    std::vector<std::string> args;
-                    while (ai != arg_names.end())
-                        args.push_back(get_symbol(*ai++));
-                    return make_lambda(args, *i);
+                    // (define (f x) ...body...)
+                    utree const& decl = *i++;
+                    Iterator di = decl.begin();
+                    fname = get_symbol(*di++);
+                    while (di != decl.end())
+                        args.push_back(get_symbol(*di++));
                 }
-
-                // (f x)
-                std::pair<compiled_function*, int> r = env.find(name);
-                if (r.first)
+                else
                 {
-                    actor_list flist;
-                    Iterator i = range.begin(); ++i;
-                    for (; i != range.end(); ++i)
-                        flist.push_back(
-                            compile(*i, env, fragments, line, source_file));
+                    // (define f ...body...)
+                    fname = get_symbol(*i++);
 
-                    // Arity check
-                    if (r.second < 0) // non-fixed arity
+                    // (define f (lambda (x) ...body...))
+                    if (i->which() == utree_type::list_type
+                        && get_symbol((*i)[0]) == "lambda")
                     {
-                        if (int(flist.size()) < -r.second)
-                            throw incorrect_arity();
+                        utree const& arg_names = (*i)[1];
+                        Iterator ai = arg_names.begin();
+                        while (ai != arg_names.end())
+                            args.push_back(get_symbol(*ai++));
                     }
-                    else // fixed arity
-                    {
-                        if (int(flist.size()) != r.second)
-                            throw incorrect_arity();
-                    }
-                    return (*r.first)(flist);
                 }
 
-                throw unknown_expression();
+                return define_function(fname, args, *i);
             }
 
-            catch (scheme_exception const& x)
+            if (name == "lambda")
             {
-                if (source_file != "")
-                    std::cerr << source_file;
+                // (lambda (x) ...body...)
+                Iterator i = range.begin(); ++i;
+                utree const& arg_names = *i++;
+                Iterator ai = arg_names.begin();
+                std::vector<std::string> args;
+                while (ai != arg_names.end())
+                    args.push_back(get_symbol(*ai++));
+                return make_lambda(args, *i);
+            }
 
-                if (line != -1)
-                    std::cerr << '(' << line << ')';
+            // (f x)
+            std::pair<compiled_function*, int> r = env.find(name);
+            if (r.first)
+            {
+                actor_list flist;
+                Iterator i = range.begin(); ++i;
+                for (; i != range.end(); ++i)
+                    flist.push_back(
+                        compile(*i, env, fragments, line, source_file));
 
-                std::cerr << " : Error! "  << x.what() << std::endl;
+                // Arity check
+                if (r.second < 0) // non-fixed arity
+                {
+                    if (int(flist.size()) < -r.second)
+                        throw incorrect_arity();
+                }
+                else // fixed arity
+                {
+                    if (int(flist.size()) != r.second)
+                        throw incorrect_arity();
+                }
+                return (*r.first)(flist);
+            }
+            else
+            {
+                throw identifier_not_found(name);
             }
 
+            // Just return the list $$$ TODO $$$ how do we disambiguate lists
+            // and function calls?
             return function();
         }
 
         static std::string get_symbol(utree const& s)
         {
+            if (s.which() != utree_type::symbol_type)
+                throw identifier_expected();
             utf8_symbol_range symbol = s.as<utf8_symbol_range>();
             return std::string(symbol.begin(), symbol.end());
         }
@@ -296,8 +324,25 @@
     {
         int line = (ast.which() == utree_type::list_type)
             ? ast.tag() : parent_line;
-        return utree::visit(ast,
-            compiler(env, fragments, line, source_file));
+
+        try
+        {
+            return utree::visit(ast,
+                compiler(env, fragments, line, source_file));
+        }
+        catch (scheme_exception const& x)
+        {
+            if (source_file != "")
+                std::cerr << source_file;
+
+            if (line != -1)
+                std::cerr << '(' << line << ')';
+
+            std::cerr << " : Error! "  << x.what() << std::endl;
+            throw compilation_error();
+        }
+
+        return function();
     }
 
     void compile_all(
@@ -311,8 +356,15 @@
             ? ast.tag() : 1;
         BOOST_FOREACH(utree const& program, ast)
         {
-            scheme::function
+            scheme::function f;
+            try
+            {
                 f = compile(program, env, fragments, line, source_file);
+            }
+            catch (compilation_error const& x)
+            {
+                continue; // try the next expression
+            }
             results.push_back(f);
         }
     }
@@ -341,15 +393,10 @@
             if (outer == 0)
                 build_basic_environment(env);
 
-            if (input::parse_sexpr_list(in, program))
+            if (input::parse_sexpr_list(in, program, source_file))
             {
                 compile_all(program, env, flist, fragments, source_file);
             }
-            else
-            {
-                // $$$ Use exceptions $$$
-                BOOST_ASSERT(false);
-            }
         }
 
         interpreter(utree const& program, environment* outer = 0)
@@ -364,6 +411,11 @@
             return flist.back()(args);
         }
 
+        bool empty() const
+        {
+            return flist.empty() || flist.back().empty();
+        }
+
         environment env;
         utree program;
         actor_list fragments;

Modified: trunk/libs/spirit/example/scheme/scheme/interpreter.hpp
==============================================================================
--- trunk/libs/spirit/example/scheme/scheme/interpreter.hpp	(original)
+++ trunk/libs/spirit/example/scheme/scheme/interpreter.hpp	2010-04-18 22:31:08 EDT (Sun, 18 Apr 2010)
@@ -171,6 +171,45 @@
     function const _10 = arg(10);
 
     ///////////////////////////////////////////////////////////////////////////
+    // variable arguments.
+    // Collects the arguments from n to last in a utree list.
+    ///////////////////////////////////////////////////////////////////////////
+    struct vararg_function : actor<vararg_function>
+    {
+        std::size_t n;
+        vararg_function(std::size_t n) : n(n) {}
+
+        utree eval(args_type args) const
+        {
+            utree result;
+            for (std::size_t i = n; i < args.size(); ++i)
+                result.push_back(boost::ref(args[i]));
+            return result;
+        }
+    };
+
+    struct vararg
+    {
+        typedef function result_type;
+        function operator()(std::size_t n) const
+        {
+            return function(vararg_function(n));
+        }
+    };
+
+    vararg const varg = {};
+    function const _1_ = varg(0);
+    function const _2_ = varg(1);
+    function const _3_ = varg(2);
+    function const _4_ = varg(3);
+    function const _5_ = varg(4);
+    function const _6_ = varg(5);
+    function const _7_ = varg(6);
+    function const _8_ = varg(7);
+    function const _9_ = varg(8);
+    function const _10_ = varg(10);
+
+    ///////////////////////////////////////////////////////////////////////////
     // composite
     ///////////////////////////////////////////////////////////////////////////
     template <typename Derived>

Added: trunk/libs/spirit/example/scheme/test/scheme/scheme_error.scm
==============================================================================
--- (empty file)
+++ trunk/libs/spirit/example/scheme/test/scheme/scheme_error.scm	2010-04-18 22:31:08 EDT (Sun, 18 Apr 2010)
@@ -0,0 +1,21 @@
+blah ; blah not found
+
+(define
+  (foo x)
+    (+ x 456))
+
+(define
+  (bar x)
+    (+ x y)) ; y not found
+
+(foo 123)
+(foo z) ; z not found
+
+(define foo 123) ; redefinition
+
+(foo 123 456) ; incorrect arity
+
+(bar 999) ; bar should not be found
+
+
+