Ditch gcc 4.6 support

8 files changed, 155 insertions, 155 deletions

diff --git a/src/io/cxxstdio.hpp b/src/io/cxxstdio.hpp
index 66419df..a2faa18 100644
--- a/src/io/cxxstdio.hpp
+++ b/src/io/cxxstdio.hpp
@@ -192,7 +192,7 @@ namespace cxxstdio
         int print(T&& t, A&&... a)
         {
             constexpr static
-            const char *print_format = Format::print_format();
+            const char *print_format = Format::print_format().format_string();
             return do_print(std::forward<T>(t), print_format,
                     decay_for_printf(convert_for_printf(std::forward<A>(a)))...);
         }
@@ -207,7 +207,7 @@ namespace cxxstdio
         int scan(T&& t, A&&... a)
         {
             constexpr static
-            const char *scan_format = Format::scan_format();
+            const char *scan_format = Format::scan_format().format_string();
             return do_scan(std::forward<T>(t), scan_format,
                     &convert_for_scanf(*a)...);
         }
@@ -218,7 +218,7 @@ namespace cxxstdio
         struct format_impl                                                  \
         {                                                                   \
             constexpr static                                                \
-            const char *print_format() { return fmt; }                      \
+            FormatString print_format() { return fmt; }                     \
         };                                                                  \
         cxxstdio::PrintFormatter<format_impl>::print(out, ## __VA_ARGS__);  \
     })
@@ -228,7 +228,7 @@ namespace cxxstdio
         struct format_impl                                                  \
         {                                                                   \
             constexpr static                                                \
-            const char *scan_format() { return fmt; }                       \
+            FormatString scan_format() { return fmt; }                      \
         };                                                                  \
         cxxstdio::ScanFormatter<format_impl>::scan(out, ## __VA_ARGS__);    \
     })
diff --git a/src/io/line.cpp b/src/io/line.cpp
index f7470a6..8451b87 100644
--- a/src/io/line.cpp
+++ b/src/io/line.cpp
@@ -36,26 +36,26 @@ namespace io
     {
         MString out;
         if (column)
-            out += STRPRINTF("%s:%u:%u: %s: %s\n",
+            out += STRPRINTF("%s:%u:%u: %s: %s\n"_fmt,
                     filename, line, column, cat, msg);
         else
-            out += STRPRINTF("%s:%u: %s: %s\n",
+            out += STRPRINTF("%s:%u: %s: %s\n"_fmt,
                     filename, line, cat, msg);
-        out += STRPRINTF("%s\n", text);
-        out += STRPRINTF("%*c\n", column, '^');
+        out += STRPRINTF("%s\n"_fmt, text);
+        out += STRPRINTF("%*c\n"_fmt, column, '^');
         return AString(out);
     }
 
     void Line::message(ZString cat, ZString msg) const
     {
         if (column)
-            FPRINTF(stderr, "%s:%u:%u: %s: %s\n",
+            FPRINTF(stderr, "%s:%u:%u: %s: %s\n"_fmt,
                     filename, line, column, cat, msg);
         else
-            FPRINTF(stderr, "%s:%u: %s: %s\n",
+            FPRINTF(stderr, "%s:%u: %s: %s\n"_fmt,
                     filename, line, cat, msg);
-        FPRINTF(stderr, "%s\n", text);
-        FPRINTF(stderr, "%*c\n", column, '^');
+        FPRINTF(stderr, "%s\n"_fmt, text);
+        FPRINTF(stderr, "%*c\n"_fmt, column, '^');
     }
 
     AString LineSpan::message_str(ZString cat, ZString msg) const
@@ -67,24 +67,24 @@ namespace io
         MString out;
         if (begin.line == end.line)
         {
-            out += STRPRINTF("%s:%u:%u: %s: %s\n",
+            out += STRPRINTF("%s:%u:%u: %s: %s\n"_fmt,
                     begin.filename, begin.line, begin.column, cat, msg);
-            out += STRPRINTF("%s\n", begin.text);
-            out += STRPRINTF("%*c", begin.column, '^');
+            out += STRPRINTF("%s\n"_fmt, begin.text);
+            out += STRPRINTF("%*c"_fmt, begin.column, '^');
             for (unsigned c = begin.column; c != end.column; ++c)
                 out += '~';
             out += '\n';
         }
         else
         {
-            out += STRPRINTF("%s:%u:%u: %s: %s\n",
+            out += STRPRINTF("%s:%u:%u: %s: %s\n"_fmt,
                     begin.filename, begin.line, begin.column, cat, msg);
-            out += STRPRINTF("%s\n", begin.text);
-            out += STRPRINTF("%*c", begin.column, '^');
+            out += STRPRINTF("%s\n"_fmt, begin.text);
+            out += STRPRINTF("%*c"_fmt, begin.column, '^');
             for (unsigned c = begin.column; c != begin.text.size(); ++c)
                 out += '~';
-            out += " ...\n";
-            out += STRPRINTF("%s\n", end.text);
+            out += " ...\n"_s;
+            out += STRPRINTF("%s\n"_fmt, end.text);
             for (unsigned c = 0; c != end.column; ++c)
                 out += '~';
             out += '\n';
@@ -94,7 +94,7 @@ namespace io
 
     void LineSpan::message(ZString cat, ZString msg) const
     {
-        FPRINTF(stderr, "%s", message_str(cat, msg));
+        FPRINTF(stderr, "%s"_fmt, message_str(cat, msg));
     }
 
     LineReader::LineReader(ZString name)
diff --git a/src/io/line.hpp b/src/io/line.hpp
index a9e8944..bb002b8 100644
--- a/src/io/line.hpp
+++ b/src/io/line.hpp
@@ -42,9 +42,9 @@ namespace io
 
         AString message_str(ZString cat, ZString msg) const;
         void message(ZString cat, ZString msg) const;
-        void note(ZString msg) const { message("note", msg); }
-        void warning(ZString msg) const { message("warning", msg); }
-        void error(ZString msg) const { message("error", msg); }
+        void note(ZString msg) const { message("note"_s, msg); }
+        void warning(ZString msg) const { message("warning"_s, msg); }
+        void error(ZString msg) const { message("error"_s, msg); }
     };
 
     // psst, don't tell anyone
@@ -65,9 +65,9 @@ namespace io
 
         AString message_str(ZString cat, ZString msg) const;
         void message(ZString cat, ZString msg) const;
-        void note(ZString msg) const { message("note", msg); }
-        void warning(ZString msg) const { message("warning", msg); }
-        void error(ZString msg) const { message("error", msg); }
+        void note(ZString msg) const { message("note"_s, msg); }
+        void warning(ZString msg) const { message("warning"_s, msg); }
+        void error(ZString msg) const { message("error"_s, msg); }
     };
 
     class LineReader
diff --git a/src/io/line_test.cpp b/src/io/line_test.cpp
index feee1fb..921e4c8 100644
--- a/src/io/line_test.cpp
+++ b/src/io/line_test.cpp
@@ -42,80 +42,80 @@ io::FD string_pipe(ZString sz)
 
 TEST(io, line1)
 {
-    io::LineReader lr("<string1>", string_pipe("Hello World\n"));
+    io::LineReader lr("<string1>"_s, string_pipe("Hello World\n"_s));
     io::Line hi;
     EXPECT_TRUE(lr.read_line(hi));
-    EXPECT_EQ(hi.text, "Hello World");
-    EXPECT_EQ(hi.filename, "<string1>");
+    EXPECT_EQ(hi.text, "Hello World"_s);
+    EXPECT_EQ(hi.filename, "<string1>"_s);
     EXPECT_EQ(hi.line, 1);
     EXPECT_EQ(hi.column, 0);
     EXPECT_FALSE(lr.read_line(hi));
 }
 TEST(io, line2)
 {
-    io::LineReader lr("<string2>", string_pipe("Hello\nWorld"));
+    io::LineReader lr("<string2>"_s, string_pipe("Hello\nWorld"_s));
     io::Line hi;
     EXPECT_TRUE(lr.read_line(hi));
-    EXPECT_EQ(hi.text, "Hello");
-    EXPECT_EQ(hi.filename, "<string2>");
+    EXPECT_EQ(hi.text, "Hello"_s);
+    EXPECT_EQ(hi.filename, "<string2>"_s);
     EXPECT_EQ(hi.line, 1);
     EXPECT_EQ(hi.column, 0);
     EXPECT_TRUE(lr.read_line(hi));
-    EXPECT_EQ(hi.text, "World");
-    EXPECT_EQ(hi.filename, "<string2>");
+    EXPECT_EQ(hi.text, "World"_s);
+    EXPECT_EQ(hi.filename, "<string2>"_s);
     EXPECT_EQ(hi.line, 2);
     EXPECT_EQ(hi.column, 0);
     EXPECT_FALSE(lr.read_line(hi));
 }
 TEST(io, line3)
 {
-    io::LineReader lr("<string3>", string_pipe("Hello\rWorld"));
+    io::LineReader lr("<string3>"_s, string_pipe("Hello\rWorld"_s));
     io::Line hi;
     EXPECT_TRUE(lr.read_line(hi));
-    EXPECT_EQ(hi.text, "Hello");
-    EXPECT_EQ(hi.filename, "<string3>");
+    EXPECT_EQ(hi.text, "Hello"_s);
+    EXPECT_EQ(hi.filename, "<string3>"_s);
     EXPECT_EQ(hi.line, 1);
     EXPECT_EQ(hi.column, 0);
     EXPECT_TRUE(lr.read_line(hi));
-    EXPECT_EQ(hi.text, "World");
-    EXPECT_EQ(hi.filename, "<string3>");
+    EXPECT_EQ(hi.text, "World"_s);
+    EXPECT_EQ(hi.filename, "<string3>"_s);
     EXPECT_EQ(hi.line, 2);
     EXPECT_EQ(hi.column, 0);
     EXPECT_FALSE(lr.read_line(hi));
 }
 TEST(io, line4)
 {
-    io::LineReader lr("<string4>", string_pipe("Hello\r\nWorld"));
+    io::LineReader lr("<string4>"_s, string_pipe("Hello\r\nWorld"_s));
     io::Line hi;
     EXPECT_TRUE(lr.read_line(hi));
-    EXPECT_EQ(hi.text, "Hello");
-    EXPECT_EQ(hi.filename, "<string4>");
+    EXPECT_EQ(hi.text, "Hello"_s);
+    EXPECT_EQ(hi.filename, "<string4>"_s);
     EXPECT_EQ(hi.line, 1);
     EXPECT_EQ(hi.column, 0);
     EXPECT_TRUE(lr.read_line(hi));
-    EXPECT_EQ(hi.text, "World");
-    EXPECT_EQ(hi.filename, "<string4>");
+    EXPECT_EQ(hi.text, "World"_s);
+    EXPECT_EQ(hi.filename, "<string4>"_s);
     EXPECT_EQ(hi.line, 2);
     EXPECT_EQ(hi.column, 0);
     EXPECT_FALSE(lr.read_line(hi));
 }
 TEST(io, line5)
 {
-    io::LineReader lr("<string5>", string_pipe("Hello\n\rWorld"));
+    io::LineReader lr("<string5>"_s, string_pipe("Hello\n\rWorld"_s));
     io::Line hi;
     EXPECT_TRUE(lr.read_line(hi));
-    EXPECT_EQ(hi.text, "Hello");
-    EXPECT_EQ(hi.filename, "<string5>");
+    EXPECT_EQ(hi.text, "Hello"_s);
+    EXPECT_EQ(hi.filename, "<string5>"_s);
     EXPECT_EQ(hi.line, 1);
     EXPECT_EQ(hi.column, 0);
     EXPECT_TRUE(lr.read_line(hi));
-    EXPECT_EQ(hi.text, "");
-    EXPECT_EQ(hi.filename, "<string5>");
+    EXPECT_EQ(hi.text, ""_s);
+    EXPECT_EQ(hi.filename, "<string5>"_s);
     EXPECT_EQ(hi.line, 2);
     EXPECT_EQ(hi.column, 0);
     EXPECT_TRUE(lr.read_line(hi));
-    EXPECT_EQ(hi.text, "World");
-    EXPECT_EQ(hi.filename, "<string5>");
+    EXPECT_EQ(hi.text, "World"_s);
+    EXPECT_EQ(hi.filename, "<string5>"_s);
     EXPECT_EQ(hi.line, 3);
     EXPECT_EQ(hi.column, 0);
     EXPECT_FALSE(lr.read_line(hi));
@@ -123,47 +123,47 @@ TEST(io, line5)
 
 TEST(io, linechar1)
 {
-    io::LineCharReader lr("<stringchar1>", string_pipe("Hi Wu\n"));
+    io::LineCharReader lr("<stringchar1>"_s, string_pipe("Hi Wu\n"_s));
     io::LineChar c;
     EXPECT_TRUE(lr.get(c));
     EXPECT_EQ(c.ch(), 'H');
-    EXPECT_EQ(c.text, "Hi Wu");
-    EXPECT_EQ(c.filename, "<stringchar1>");
+    EXPECT_EQ(c.text, "Hi Wu"_s);
+    EXPECT_EQ(c.filename, "<stringchar1>"_s);
     EXPECT_EQ(c.line, 1);
     EXPECT_EQ(c.column, 1);
     lr.adv();
     EXPECT_TRUE(lr.get(c));
     EXPECT_EQ(c.ch(), 'i');
-    EXPECT_EQ(c.text, "Hi Wu");
-    EXPECT_EQ(c.filename, "<stringchar1>");
+    EXPECT_EQ(c.text, "Hi Wu"_s);
+    EXPECT_EQ(c.filename, "<stringchar1>"_s);
     EXPECT_EQ(c.line, 1);
     EXPECT_EQ(c.column, 2);
     lr.adv();
     EXPECT_TRUE(lr.get(c));
     EXPECT_EQ(c.ch(), ' ');
-    EXPECT_EQ(c.text, "Hi Wu");
-    EXPECT_EQ(c.filename, "<stringchar1>");
+    EXPECT_EQ(c.text, "Hi Wu"_s);
+    EXPECT_EQ(c.filename, "<stringchar1>"_s);
     EXPECT_EQ(c.line, 1);
     EXPECT_EQ(c.column, 3);
     lr.adv();
     EXPECT_TRUE(lr.get(c));
     EXPECT_EQ(c.ch(), 'W');
-    EXPECT_EQ(c.text, "Hi Wu");
-    EXPECT_EQ(c.filename, "<stringchar1>");
+    EXPECT_EQ(c.text, "Hi Wu"_s);
+    EXPECT_EQ(c.filename, "<stringchar1>"_s);
     EXPECT_EQ(c.line, 1);
     EXPECT_EQ(c.column, 4);
     lr.adv();
     EXPECT_TRUE(lr.get(c));
     EXPECT_EQ(c.ch(), 'u');
-    EXPECT_EQ(c.text, "Hi Wu");
-    EXPECT_EQ(c.filename, "<stringchar1>");
+    EXPECT_EQ(c.text, "Hi Wu"_s);
+    EXPECT_EQ(c.filename, "<stringchar1>"_s);
     EXPECT_EQ(c.line, 1);
     EXPECT_EQ(c.column, 5);
     lr.adv();
     EXPECT_TRUE(lr.get(c));
     EXPECT_EQ(c.ch(), '\n');
-    EXPECT_EQ(c.text, "Hi Wu");
-    EXPECT_EQ(c.filename, "<stringchar1>");
+    EXPECT_EQ(c.text, "Hi Wu"_s);
+    EXPECT_EQ(c.filename, "<stringchar1>"_s);
     EXPECT_EQ(c.line, 1);
     EXPECT_EQ(c.column, 6);
     lr.adv();
@@ -171,47 +171,47 @@ TEST(io, linechar1)
 }
 TEST(io, linechar2)
 {
-    io::LineCharReader lr("<stringchar2>", string_pipe("Hi\nWu"));
+    io::LineCharReader lr("<stringchar2>"_s, string_pipe("Hi\nWu"_s));
     io::LineChar c;
     EXPECT_TRUE(lr.get(c));
     EXPECT_EQ(c.ch(), 'H');
-    EXPECT_EQ(c.text, "Hi");
-    EXPECT_EQ(c.filename, "<stringchar2>");
+    EXPECT_EQ(c.text, "Hi"_s);
+    EXPECT_EQ(c.filename, "<stringchar2>"_s);
     EXPECT_EQ(c.line, 1);
     EXPECT_EQ(c.column, 1);
     lr.adv();
     EXPECT_TRUE(lr.get(c));
     EXPECT_EQ(c.ch(), 'i');
-    EXPECT_EQ(c.text, "Hi");
-    EXPECT_EQ(c.filename, "<stringchar2>");
+    EXPECT_EQ(c.text, "Hi"_s);
+    EXPECT_EQ(c.filename, "<stringchar2>"_s);
     EXPECT_EQ(c.line, 1);
     EXPECT_EQ(c.column, 2);
     lr.adv();
     EXPECT_TRUE(lr.get(c));
     EXPECT_EQ(c.ch(), '\n');
-    EXPECT_EQ(c.text, "Hi");
-    EXPECT_EQ(c.filename, "<stringchar2>");
+    EXPECT_EQ(c.text, "Hi"_s);
+    EXPECT_EQ(c.filename, "<stringchar2>"_s);
     EXPECT_EQ(c.line, 1);
     EXPECT_EQ(c.column, 3);
     lr.adv();
     EXPECT_TRUE(lr.get(c));
     EXPECT_EQ(c.ch(), 'W');
-    EXPECT_EQ(c.text, "Wu");
-    EXPECT_EQ(c.filename, "<stringchar2>");
+    EXPECT_EQ(c.text, "Wu"_s);
+    EXPECT_EQ(c.filename, "<stringchar2>"_s);
     EXPECT_EQ(c.line, 2);
     EXPECT_EQ(c.column, 1);
     lr.adv();
     EXPECT_TRUE(lr.get(c));
     EXPECT_EQ(c.ch(), 'u');
-    EXPECT_EQ(c.text, "Wu");
-    EXPECT_EQ(c.filename, "<stringchar2>");
+    EXPECT_EQ(c.text, "Wu"_s);
+    EXPECT_EQ(c.filename, "<stringchar2>"_s);
     EXPECT_EQ(c.line, 2);
     EXPECT_EQ(c.column, 2);
     lr.adv();
     EXPECT_TRUE(lr.get(c));
     EXPECT_EQ(c.ch(), '\n');
-    EXPECT_EQ(c.text, "Wu");
-    EXPECT_EQ(c.filename, "<stringchar2>");
+    EXPECT_EQ(c.text, "Wu"_s);
+    EXPECT_EQ(c.filename, "<stringchar2>"_s);
     EXPECT_EQ(c.line, 2);
     EXPECT_EQ(c.column, 3);
     lr.adv();
@@ -219,47 +219,47 @@ TEST(io, linechar2)
 }
 TEST(io, linechar3)
 {
-    io::LineCharReader lr("<stringchar3>", string_pipe("Hi\rWu"));
+    io::LineCharReader lr("<stringchar3>"_s, string_pipe("Hi\rWu"_s));
     io::LineChar c;
     EXPECT_TRUE(lr.get(c));
     EXPECT_EQ(c.ch(), 'H');
-    EXPECT_EQ(c.text, "Hi");
-    EXPECT_EQ(c.filename, "<stringchar3>");
+    EXPECT_EQ(c.text, "Hi"_s);
+    EXPECT_EQ(c.filename, "<stringchar3>"_s);
     EXPECT_EQ(c.line, 1);
     EXPECT_EQ(c.column, 1);
     lr.adv();
     EXPECT_TRUE(lr.get(c));
     EXPECT_EQ(c.ch(), 'i');
-    EXPECT_EQ(c.text, "Hi");
-    EXPECT_EQ(c.filename, "<stringchar3>");
+    EXPECT_EQ(c.text, "Hi"_s);
+    EXPECT_EQ(c.filename, "<stringchar3>"_s);
     EXPECT_EQ(c.line, 1);
     EXPECT_EQ(c.column, 2);
     lr.adv();
     EXPECT_TRUE(lr.get(c));
     EXPECT_EQ(c.ch(), '\n');
-    EXPECT_EQ(c.text, "Hi");
-    EXPECT_EQ(c.filename, "<stringchar3>");
+    EXPECT_EQ(c.text, "Hi"_s);
+    EXPECT_EQ(c.filename, "<stringchar3>"_s);
     EXPECT_EQ(c.line, 1);
     EXPECT_EQ(c.column, 3);
     lr.adv();
     EXPECT_TRUE(lr.get(c));
     EXPECT_EQ(c.ch(), 'W');
-    EXPECT_EQ(c.text, "Wu");
-    EXPECT_EQ(c.filename, "<stringchar3>");
+    EXPECT_EQ(c.text, "Wu"_s);
+    EXPECT_EQ(c.filename, "<stringchar3>"_s);
     EXPECT_EQ(c.line, 2);
     EXPECT_EQ(c.column, 1);
     lr.adv();
     EXPECT_TRUE(lr.get(c));
     EXPECT_EQ(c.ch(), 'u');
-    EXPECT_EQ(c.text, "Wu");
-    EXPECT_EQ(c.filename, "<stringchar3>");
+    EXPECT_EQ(c.text, "Wu"_s);
+    EXPECT_EQ(c.filename, "<stringchar3>"_s);
     EXPECT_EQ(c.line, 2);
     EXPECT_EQ(c.column, 2);
     lr.adv();
     EXPECT_TRUE(lr.get(c));
     EXPECT_EQ(c.ch(), '\n');
-    EXPECT_EQ(c.text, "Wu");
-    EXPECT_EQ(c.filename, "<stringchar3>");
+    EXPECT_EQ(c.text, "Wu"_s);
+    EXPECT_EQ(c.filename, "<stringchar3>"_s);
     EXPECT_EQ(c.line, 2);
     EXPECT_EQ(c.column, 3);
     lr.adv();
@@ -267,47 +267,47 @@ TEST(io, linechar3)
 }
 TEST(io, linechar4)
 {
-    io::LineCharReader lr("<stringchar4>", string_pipe("Hi\r\nWu"));
+    io::LineCharReader lr("<stringchar4>"_s, string_pipe("Hi\r\nWu"_s));
     io::LineChar c;
     EXPECT_TRUE(lr.get(c));
     EXPECT_EQ(c.ch(), 'H');
-    EXPECT_EQ(c.text, "Hi");
-    EXPECT_EQ(c.filename, "<stringchar4>");
+    EXPECT_EQ(c.text, "Hi"_s);
+    EXPECT_EQ(c.filename, "<stringchar4>"_s);
     EXPECT_EQ(c.line, 1);
     EXPECT_EQ(c.column, 1);
     lr.adv();
     EXPECT_TRUE(lr.get(c));
     EXPECT_EQ(c.ch(), 'i');
-    EXPECT_EQ(c.text, "Hi");
-    EXPECT_EQ(c.filename, "<stringchar4>");
+    EXPECT_EQ(c.text, "Hi"_s);
+    EXPECT_EQ(c.filename, "<stringchar4>"_s);
     EXPECT_EQ(c.line, 1);
     EXPECT_EQ(c.column, 2);
     lr.adv();
     EXPECT_TRUE(lr.get(c));
     EXPECT_EQ(c.ch(), '\n');
-    EXPECT_EQ(c.text, "Hi");
-    EXPECT_EQ(c.filename, "<stringchar4>");
+    EXPECT_EQ(c.text, "Hi"_s);
+    EXPECT_EQ(c.filename, "<stringchar4>"_s);
     EXPECT_EQ(c.line, 1);
     EXPECT_EQ(c.column, 3);
     lr.adv();
     EXPECT_TRUE(lr.get(c));
     EXPECT_EQ(c.ch(), 'W');
-    EXPECT_EQ(c.text, "Wu");
-    EXPECT_EQ(c.filename, "<stringchar4>");
+    EXPECT_EQ(c.text, "Wu"_s);
+    EXPECT_EQ(c.filename, "<stringchar4>"_s);
     EXPECT_EQ(c.line, 2);
     EXPECT_EQ(c.column, 1);
     lr.adv();
     EXPECT_TRUE(lr.get(c));
     EXPECT_EQ(c.ch(), 'u');
-    EXPECT_EQ(c.text, "Wu");
-    EXPECT_EQ(c.filename, "<stringchar4>");
+    EXPECT_EQ(c.text, "Wu"_s);
+    EXPECT_EQ(c.filename, "<stringchar4>"_s);
     EXPECT_EQ(c.line, 2);
     EXPECT_EQ(c.column, 2);
     lr.adv();
     EXPECT_TRUE(lr.get(c));
     EXPECT_EQ(c.ch(), '\n');
-    EXPECT_EQ(c.text, "Wu");
-    EXPECT_EQ(c.filename, "<stringchar4>");
+    EXPECT_EQ(c.text, "Wu"_s);
+    EXPECT_EQ(c.filename, "<stringchar4>"_s);
     EXPECT_EQ(c.line, 2);
     EXPECT_EQ(c.column, 3);
     lr.adv();
@@ -315,54 +315,54 @@ TEST(io, linechar4)
 }
 TEST(io, linechar5)
 {
-    io::LineCharReader lr("<stringchar5>", string_pipe("Hi\n\rWu"));
+    io::LineCharReader lr("<stringchar5>"_s, string_pipe("Hi\n\rWu"_s));
     io::LineChar c;
     EXPECT_TRUE(lr.get(c));
     EXPECT_EQ(c.ch(), 'H');
-    EXPECT_EQ(c.text, "Hi");
-    EXPECT_EQ(c.filename, "<stringchar5>");
+    EXPECT_EQ(c.text, "Hi"_s);
+    EXPECT_EQ(c.filename, "<stringchar5>"_s);
     EXPECT_EQ(c.line, 1);
     EXPECT_EQ(c.column, 1);
     lr.adv();
     EXPECT_TRUE(lr.get(c));
     EXPECT_EQ(c.ch(), 'i');
-    EXPECT_EQ(c.text, "Hi");
-    EXPECT_EQ(c.filename, "<stringchar5>");
+    EXPECT_EQ(c.text, "Hi"_s);
+    EXPECT_EQ(c.filename, "<stringchar5>"_s);
     EXPECT_EQ(c.line, 1);
     EXPECT_EQ(c.column, 2);
     lr.adv();
     EXPECT_TRUE(lr.get(c));
     EXPECT_EQ(c.ch(), '\n');
-    EXPECT_EQ(c.text, "Hi");
-    EXPECT_EQ(c.filename, "<stringchar5>");
+    EXPECT_EQ(c.text, "Hi"_s);
+    EXPECT_EQ(c.filename, "<stringchar5>"_s);
     EXPECT_EQ(c.line, 1);
     EXPECT_EQ(c.column, 3);
     lr.adv();
     EXPECT_TRUE(lr.get(c));
     EXPECT_EQ(c.ch(), '\n');
-    EXPECT_EQ(c.text, "");
-    EXPECT_EQ(c.filename, "<stringchar5>");
+    EXPECT_EQ(c.text, ""_s);
+    EXPECT_EQ(c.filename, "<stringchar5>"_s);
     EXPECT_EQ(c.line, 2);
     EXPECT_EQ(c.column, 1);
     lr.adv();
     EXPECT_TRUE(lr.get(c));
     EXPECT_EQ(c.ch(), 'W');
-    EXPECT_EQ(c.text, "Wu");
-    EXPECT_EQ(c.filename, "<stringchar5>");
+    EXPECT_EQ(c.text, "Wu"_s);
+    EXPECT_EQ(c.filename, "<stringchar5>"_s);
     EXPECT_EQ(c.line, 3);
     EXPECT_EQ(c.column, 1);
     lr.adv();
     EXPECT_TRUE(lr.get(c));
     EXPECT_EQ(c.ch(), 'u');
-    EXPECT_EQ(c.text, "Wu");
-    EXPECT_EQ(c.filename, "<stringchar5>");
+    EXPECT_EQ(c.text, "Wu"_s);
+    EXPECT_EQ(c.filename, "<stringchar5>"_s);
     EXPECT_EQ(c.line, 3);
     EXPECT_EQ(c.column, 2);
     lr.adv();
     EXPECT_TRUE(lr.get(c));
     EXPECT_EQ(c.ch(), '\n');
-    EXPECT_EQ(c.text, "Wu");
-    EXPECT_EQ(c.filename, "<stringchar5>");
+    EXPECT_EQ(c.text, "Wu"_s);
+    EXPECT_EQ(c.filename, "<stringchar5>"_s);
     EXPECT_EQ(c.line, 3);
     EXPECT_EQ(c.column, 3);
     lr.adv();
@@ -371,7 +371,7 @@ TEST(io, linechar5)
 
 TEST(io, linespan)
 {
-    io::LineCharReader lr("<span>", string_pipe("Hello,\nWorld!\n"));
+    io::LineCharReader lr("<span>"_s, string_pipe("Hello,\nWorld!\n"_s));
     io::LineSpan span;
     do
     {
@@ -385,10 +385,10 @@ TEST(io, linespan)
         lr.adv();
     }
     while (span.end.ch() != 'o');
-    EXPECT_EQ(span.message_str("info", "meh"),
+    EXPECT_EQ(span.message_str("info"_s, "meh"_s),
             "<span>:1:2: info: meh\n"
             "Hello,\n"
-            " ^~~~\n"
+            " ^~~~\n"_s
     );
     span.begin = span.end;
     do
@@ -398,21 +398,21 @@ TEST(io, linespan)
     }
     while (span.end.ch() != 'r');
 
-    EXPECT_EQ(span.begin.message_str("note", "foo"),
+    EXPECT_EQ(span.begin.message_str("note"_s, "foo"_s),
             "<span>:1:5: note: foo\n"
             "Hello,\n"
-            "    ^\n"
+            "    ^\n"_s
     );
-    EXPECT_EQ(span.end.message_str("warning", "bar"),
+    EXPECT_EQ(span.end.message_str("warning"_s, "bar"_s),
             "<span>:2:3: warning: bar\n"
             "World!\n"
-            "  ^\n"
+            "  ^\n"_s
     );
-    EXPECT_EQ(span.message_str("error", "qux"),
+    EXPECT_EQ(span.message_str("error"_s, "qux"_s),
             "<span>:1:5: error: qux\n"
             "Hello,\n"
             "    ^~ ...\n"
             "World!\n"
-            "~~~\n"
+            "~~~\n"_s
     );
 }
diff --git a/src/io/lock.cpp b/src/io/lock.cpp
index 96c3649..1342915 100644
--- a/src/io/lock.cpp
+++ b/src/io/lock.cpp
@@ -49,7 +49,7 @@ namespace io
         AString newfile;
         do
         {
-            newfile = STRPRINTF("%s_%d.tmp", filename, no++);
+            newfile = STRPRINTF("%s_%d.tmp"_fmt, filename, no++);
             fd = FD::open(newfile, O_WRONLY | O_CREAT | O_EXCL, 0666);
         }
         while (fd == FD() && errno == EEXIST);
@@ -67,21 +67,21 @@ namespace io
         if (!WriteFile::close())
         {
             // leave partial file
-            FPRINTF(stderr, "Warning: failed to write replacement for %s\n", filename);
+            FPRINTF(stderr, "Warning: failed to write replacement for %s\n"_fmt, filename);
             abort();
         }
 
         int n = backup_count;
-        AString old_filename = STRPRINTF("%s.%d", filename, n);
+        AString old_filename = STRPRINTF("%s.%d"_fmt, filename, n);
         while (--n)
         {
-            AString newer_filename = STRPRINTF("%s.%d", filename, n);
+            AString newer_filename = STRPRINTF("%s.%d"_fmt, filename, n);
             rename(newer_filename.c_str(), old_filename.c_str());
             old_filename = std::move(newer_filename);
         }
         rename(filename.c_str(), old_filename.c_str());
 
-        AString tmpfile = STRPRINTF("%s_%d.tmp", filename, tmp_suffix);
+        AString tmpfile = STRPRINTF("%s_%d.tmp"_fmt, filename, tmp_suffix);
         rename(tmpfile.c_str(), filename.c_str());
     }
 } // namespace io
diff --git a/src/io/read.cpp b/src/io/read.cpp
index 2ef35cc..61a6256 100644
--- a/src/io/read.cpp
+++ b/src/io/read.cpp
@@ -105,12 +105,12 @@ namespace io
         if (unhappy)
         {
             if (happy)
-                PRINTF("warning: file contains CR\n");
+                PRINTF("warning: file contains CR\n"_fmt);
             else
-                PRINTF("warning: file contains bare CR\n");
+                PRINTF("warning: file contains bare CR\n"_fmt);
         }
         else if (!happy && anything)
-            PRINTF("warning: file does not contain a trailing newline\n");
+            PRINTF("warning: file does not contain a trailing newline\n"_fmt);
         line = AString(tmp);
         return anything;
     }
diff --git a/src/io/read_test.cpp b/src/io/read_test.cpp
index 87f95ba..398c01e 100644
--- a/src/io/read_test.cpp
+++ b/src/io/read_test.cpp
@@ -42,42 +42,42 @@ io::FD string_pipe(ZString sz)
 
 TEST(io, read1)
 {
-    io::ReadFile rf(string_pipe("Hello"));
+    io::ReadFile rf(string_pipe("Hello"_s));
     AString hi;
     EXPECT_TRUE(rf.getline(hi));
-    EXPECT_EQ(hi, "Hello");
+    EXPECT_EQ(hi, "Hello"_s);
     EXPECT_FALSE(rf.getline(hi));
 }
 TEST(io, read2)
 {
-    io::ReadFile rf(string_pipe("Hello\n"));
+    io::ReadFile rf(string_pipe("Hello\n"_s));
     AString hi;
     EXPECT_TRUE(rf.getline(hi));
-    EXPECT_EQ(hi, "Hello");
+    EXPECT_EQ(hi, "Hello"_s);
     EXPECT_FALSE(rf.getline(hi));
 }
 TEST(io, read3)
 {
-    io::ReadFile rf(string_pipe("Hello\r"));
+    io::ReadFile rf(string_pipe("Hello\r"_s));
     AString hi;
     EXPECT_TRUE(rf.getline(hi));
-    EXPECT_EQ(hi, "Hello");
+    EXPECT_EQ(hi, "Hello"_s);
     EXPECT_FALSE(rf.getline(hi));
 }
 TEST(io, read4)
 {
-    io::ReadFile rf(string_pipe("Hello\r\n"));
+    io::ReadFile rf(string_pipe("Hello\r\n"_s));
     AString hi;
     EXPECT_TRUE(rf.getline(hi));
-    EXPECT_EQ(hi, "Hello");
+    EXPECT_EQ(hi, "Hello"_s);
     EXPECT_FALSE(rf.getline(hi));
 }
 TEST(io, read5)
 {
-    io::ReadFile rf(string_pipe("Hello\n\r"));
+    io::ReadFile rf(string_pipe("Hello\n\r"_s));
     AString hi;
     EXPECT_TRUE(rf.getline(hi));
-    EXPECT_EQ(hi, "Hello");
+    EXPECT_EQ(hi, "Hello"_s);
     EXPECT_TRUE(rf.getline(hi));
     EXPECT_FALSE(hi);
     EXPECT_FALSE(rf.getline(hi));
diff --git a/src/io/write_test.cpp b/src/io/write_test.cpp
index ae8eccd..5419501 100644
--- a/src/io/write_test.cpp
+++ b/src/io/write_test.cpp
@@ -65,7 +65,7 @@ public:
             if (rv == -1)
             {
                 if (errno != EAGAIN)
-                    return {"Error, read failed :("};
+                    return "Error, read failed :("_s;
                 rv = 0;
             }
             if (rv == 0)
@@ -81,11 +81,11 @@ TEST(io, write1)
     PipeWriter pw(false);
     io::WriteFile& wf = pw.wf;
     wf.really_put("Hello, ", 7);
-    EXPECT_EQ("", pw.slurp());
-    wf.put_line("World!\n");
-    EXPECT_EQ("", pw.slurp());
+    EXPECT_EQ(""_s, pw.slurp());
+    wf.put_line("World!\n"_s);
+    EXPECT_EQ(""_s, pw.slurp());
     EXPECT_TRUE(wf.close());
-    EXPECT_EQ("Hello, World!\n", pw.slurp());
+    EXPECT_EQ("Hello, World!\n"_s, pw.slurp());
 }
 
 TEST(io, write2)
@@ -93,10 +93,10 @@ TEST(io, write2)
     PipeWriter pw(true);
     io::WriteFile& wf = pw.wf;
     wf.really_put("Hello, ", 7);
-    EXPECT_EQ("", pw.slurp());
-    wf.put_line("World!");
+    EXPECT_EQ(""_s, pw.slurp());
+    wf.put_line("World!"_s);
     wf.really_put("XXX", 3);
-    EXPECT_EQ("Hello, World!\n", pw.slurp());
+    EXPECT_EQ("Hello, World!\n"_s, pw.slurp());
     EXPECT_TRUE(wf.close());
-    EXPECT_EQ("XXX", pw.slurp());
+    EXPECT_EQ("XXX"_s, pw.slurp());
 }