Changeset d03a386 for libcfa/src/collections/string.hfa

Timestamp:

Apr 11, 2025, 1:23:39 AM (9 months ago)

Author:

Michael Brooks <mlbrooks@…>

Branches:

master

Children:

dab6e39

Parents:

570e7ad

Message:

Give a few string operator overloads a preference boost.

Intent is to approximate: When selecting +/* candidates, treat it ambiguous until finding a user-given arithmetic-vs-string constraint, such as assigning the result to a string. Once a string interpretation is imposed, prefer an alternative that converts to string as soon as possible.

This description is not directly achievable with the CFA type system. The approximation has the known flaw shown in the string-operator test, where a fairly built-up expression that should be ambiguous is actually defaulting to the string version.

This change is the last of the string-overload reorganizations that the string-operator test was originally meant to illustrate. In Mike's opinion, the resulting state is ideal, except for the just-mentioned flaw.

File:

• libcfa/src/collections/string.hfa (modified) (6 diffs)

libcfa/src/collections/string.hfa

@@ -19 +19 @@
 #include <string_res.hfa>
 
+static struct __cfa_string_preference_boost_t {} __cfa_string_preference_boost;
+#define PBOOST forall ( | { __cfa_string_preference_boost_t __cfa_string_preference_boost; } )
+
 struct string {
         string_res * inner;
@@ -28 +31 @@
 void ?{}( string & s );                                                                 // empty string
 void ?{}( string & s, string s2, size_t maxlen );
-void ?{}( string & s, string s2 );
+PBOOST void ?{}( string & s, string s2 );
 void ?{}( string & s, char );
 void ?{}( string & s, const char * c );                                 // copy from string literal (NULL-terminated)
@@ -48 +51 @@
 // string str( long double _Complex rhs );
 
-string & ?=?( string & s, string c );
+PBOOST string & ?=?( string & s, string c );
 string & ?=?( string & s, const char * c );                             // copy from "literal"
 string & ?=?( string & s, char c );                                             // copy from 'l'
@@ -162 +165 @@
 string ?+?( string s, char c );
 string ?+?( char c, string s );
-string ?+?( string s, string s2 );
+PBOOST string ?+?( string s, string s2 );
 string ?+?( const char * s, char c );                                   // not backwards compatible
 string ?+?( char c, const char * s );
@@ -184 +187 @@
 void ?*=?( string & s, strmul_factor_t factor );
 string ?*?( char c, strmul_factor_t factor );                                   // not backwards compatible
-string ?*?( string s, strmul_factor_t factor );
+PBOOST string ?*?( string s, strmul_factor_t factor );
 string ?*?( const char * s, strmul_factor_t factor );
 static inline string ?*?( strmul_factor_t factor, char s ) { return s * factor; }
-static inline string ?*?( strmul_factor_t factor, string s ) { return s * factor; }
+PBOOST static inline string ?*?( strmul_factor_t factor, string s ) { return s * factor; }
 static inline string ?*?( strmul_factor_t factor, const char * s ) { return s * factor; }
 
@@ -314 +317 @@
         return translate( S, f );
 }
+
+#ifndef _COMPILING_STRING_CFA_
+#undef PBOOST
+#endif