1 files changed, 89 insertions, 0 deletions
diff --git a/src/expand/assert.cpp b/src/expand/assert.cpp
new file mode 100644
index 00000000..1c057935
--- /dev/null
+++ b/src/expand/assert.cpp
@@ -0,0 +1,89 @@
+/*
+ * MRustC - Rust Compiler
+ * - By John Hodge (Mutabah/thePowersGang)
+ *
+ * expand/assert.cpp
+ * - assert! built-in macro (1.29)
+ */
+#include <synext_macro.hpp>
+#include <synext.hpp>   // for Expand_BareExpr
+#include <parse/interpolated_fragment.hpp>
+#include "../parse/ttstream.hpp"
+#include "../parse/common.hpp"
+#include "../parse/parseerror.hpp"
+
+class CExpander_assert:
+    public ExpandProcMacro
+{
+    ::std::unique_ptr<TokenStream> expand(const Span& sp, const ::AST::Crate& crate, const ::std::string& ident, const TokenTree& tt, AST::Module& mod) override
+    {
+        Token   tok;
+
+        auto lex = TTStream(sp, tt);
+        lex.parse_state().module = &mod;
+        if( ident != "" )
+            ERROR(sp, E0000, "format_args! doesn't take an ident");
+
+        // assertion condition
+        auto n = Parse_Expr0(lex);
+        ASSERT_BUG(sp, n, "No expression returned");
+
+        ::std::vector<TokenTree> toks;
+
+        toks.push_back( Token(TOK_RWORD_IF) );
+
+        GET_TOK(tok, lex);
+        if( tok == TOK_COMMA )
+        {
+            toks.push_back( Token(InterpolatedFragment(InterpolatedFragment::EXPR, n.release())) );
+            toks.push_back( Token(TOK_BRACE_OPEN) );
+            // User-provided message
+            toks.push_back( Token(TOK_IDENT, "panic") );
+            toks.push_back( Token(TOK_EXCLAM) );
+            toks.push_back( Token(TOK_PAREN_OPEN) );
+            while(lex.lookahead(0) != TOK_EOF )
+            {
+                toks.push_back( Token(InterpolatedFragment(InterpolatedFragment::EXPR, Parse_Expr0(lex).release())) );
+                if( lex.lookahead(0) != TOK_COMMA )
+                    break;
+                GET_CHECK_TOK(tok, lex, TOK_COMMA);
+                toks.push_back( Token(TOK_COMMA) );
+            }
+            GET_CHECK_TOK(tok, lex, TOK_EOF);
+            toks.push_back( Token(TOK_PAREN_CLOSE) );
+        }
+        else if( tok == TOK_EOF )
+        {
+            ::std::stringstream ss;
+            ss << "assertion failed: ";
+            n->print(ss);
+
+            toks.push_back( Token(InterpolatedFragment(InterpolatedFragment::EXPR, n.release())) );
+
+            toks.push_back( Token(TOK_BRACE_OPEN) );
+            // Auto-generated message
+            toks.push_back( Token(TOK_IDENT, "panic") );
+            toks.push_back( Token(TOK_EXCLAM) );
+            toks.push_back( Token(TOK_PAREN_OPEN) );
+            toks.push_back( Token(TOK_STRING, ss.str()) );
+            toks.push_back( Token(TOK_PAREN_CLOSE) );
+        }
+        else
+        {
+            throw ParseError::Unexpected(lex, tok, {TOK_COMMA, TOK_EOF});
+        }
+
+        toks.push_back( Token(TOK_BRACE_CLOSE) );
+
+        return box$( TTStreamO(sp, TokenTree(Ident::Hygiene::new_scope(), mv$(toks))) );
+    }
+};
+
+void Expand_init_assert()
+{
+    if( TARGETVER_1_29 )
+    {
+        Register_Synext_Macro("assert", ::std::unique_ptr<ExpandProcMacro>(new CExpander_assert));
+    }
+}
+