Merge string_util.h into cpp2util.h

Minus a couple of functions that aren't used

And minor touchups, mainly int_to_string using more if-constexpr

Author: hsutter

include/cpp2regex.h

@@ -3009,7 +3009,7 @@ size_t i{0};
                 char number_as_char {unsafe_narrow<char>(cpp2::move(number))}; 
 
                 auto token {CPP2_UFCS_TEMPLATE(cpp2_new<char_token>)(cpp2::shared, number_as_char, ctx.get_modifiers().has(expression_flags::case_insensitive))}; 
-                (*cpp2::impl::assert_not_null(token)).set_string("\\" + cpp2::to_string(string_util::int_to_string(cpp2::impl::as_<int>(cpp2::move(number_as_char)), 8)) + "");
+                (*cpp2::impl::assert_not_null(token)).set_string("\\" + cpp2::to_string(string_util::int_to_string<8>(cpp2::impl::as_<int>(cpp2::move(number_as_char)))) + "");
 
                 return token; 
             }
@@ -3335,7 +3335,7 @@ template<typename CharT, int group, bool case_insensitive> [[nodiscard]] auto gr
     // TODO: Change for unicode.
     char number_as_char {unsafe_narrow<char>(cpp2::move(number))}; 
 
-    std::string syntax {string_util::int_to_string(cpp2::impl::as_<int>(number_as_char), 16)}; 
+    std::string syntax {string_util::int_to_string<16>(cpp2::impl::as_<int>(number_as_char))}; 
     if (cpp2::move(has_brackets)) {
         syntax = "{" + cpp2::to_string(syntax) + "}";
     }
@@ -3471,7 +3471,7 @@ template<typename CharT, bool positive> [[nodiscard]] auto lookahead_token_match
     // TODO: Change for unicode.
     char number_as_char {unsafe_narrow<char>(cpp2::move(number))}; 
 
-    std::string syntax {"\\o{" + cpp2::to_string(string_util::int_to_string(cpp2::impl::as_<int>(number_as_char), 8)) + "}"}; 
+    std::string syntax {"\\o{" + cpp2::to_string(string_util::int_to_string<8>(cpp2::impl::as_<int>(number_as_char))) + "}"}; 
     auto r {CPP2_UFCS_TEMPLATE(cpp2_new<char_token>)(cpp2::shared, cpp2::move(number_as_char), ctx.get_modifiers().has(expression_flags::case_insensitive))}; 
     (*cpp2::impl::assert_not_null(r)).set_string(cpp2::move(syntax));
     return r; 

include/cpp2regex.h2

@@ -1568,7 +1568,7 @@ group_ref_token: @polymorphic_base type = {
                 number_as_char : char = unsafe_narrow<char>(number);
 
                 token := shared.new<char_token>(number_as_char, ctx..get_modifiers()..has(expression_flags::case_insensitive));
-                token*..set_string("\\(string_util::int_to_string(number_as_char as int, 8))$");
+                token*..set_string("\\(string_util::int_to_string<8>(number_as_char as int))$");
 
                 return token;
             }
@@ -1902,7 +1902,7 @@ hexadecimal_token_parse: (inout ctx: parse_context) -> token_ptr = {
     // TODO: Change for unicode.
     number_as_char : char = unsafe_narrow<char>(number);
 
-    syntax: std::string = string_util::int_to_string(number_as_char as int, 16);
+    syntax: std::string = string_util::int_to_string<16>(number_as_char as int);
     if has_brackets {
         syntax = "{(syntax)$}";
     }
@@ -2057,7 +2057,7 @@ octal_token_parse: (inout ctx: parse_context) -> token_ptr = {
     // TODO: Change for unicode.
     number_as_char : char = unsafe_narrow<char>(number);
 
-    syntax: std::string = "\\o{(string_util::int_to_string(number_as_char as int, 8))$}";
+    syntax: std::string = "\\o{(string_util::int_to_string<8>(number_as_char as int))$}";
     r := shared.new<char_token>(number_as_char, ctx..get_modifiers()..has(expression_flags::case_insensitive));
     r*..set_string(syntax);
     return r;

include/cpp2util.h

@@ -36,6 +36,12 @@
 //      because it can't happen; using the name impl::deferred_init directly
 //      from program code is not supported.
 // 
+//  3)  Entities in other subnamespaces, such as cpp2::string_util
+// 
+//      These are typically metafunction "runtime-library" functions,
+//      implementation details called by metafunction-generated code.
+//      For example, @regex generates code that uses string_util:: functions.
+// 
 //===========================================================================
 
 #ifndef CPP2_UTIL_H
@@ -323,8 +329,6 @@
     #define CPP2_CONSTEXPR constexpr
 #endif
 
-#include "string_util.h"
-
 namespace cpp2 {
 
 
@@ -364,6 +368,152 @@ using _schar     = signed char;      // normally use i8 instead
 using _uchar     = unsigned char;    // normally use u8 instead
 
 
+//-----------------------------------------------------------------------
+//
+//  String utilities
+//
+
+namespace string_util {
+
+//  From https://stackoverflow.com/questions/216823/how-to-trim-a-stdstring
+
+//  Trim from start (in place)
+inline void ltrim(std::string &s) {
+    s.erase(
+        s.begin(), 
+        std::find_if(s.begin(), s.end(), [](unsigned char ch) { return !std::isspace(ch); })
+    );
+}
+
+//  Trim from end (in place)
+inline void rtrim(std::string &s) {
+    s.erase(
+        std::find_if(s.rbegin(), s.rend(), [](unsigned char ch) { return !std::isspace(ch); }).base(), 
+        s.end()
+    );
+}
+
+//  Trim from both ends (in place)
+inline void trim(std::string &s) {
+    rtrim(s);
+    ltrim(s);
+}
+
+//  Trim from both ends (copying)
+inline std::string trim_copy(std::string_view s) {
+    std::string t(s);
+    trim(t);
+    return t;
+}
+
+//  From https://oleksandrkvl.github.io/2021/04/02/cpp-20-overview.html#nttp
+
+template<typename CharT, std::size_t N>
+struct fixed_string {
+    constexpr fixed_string(const CharT (&s)[N+1]) {
+        std::copy_n(s, N + 1, c_str);
+    }
+    constexpr const CharT* data() const {
+        return c_str;
+    }
+    constexpr std::size_t size() const {
+        return N;
+    }
+
+    constexpr auto str() const {
+        return std::basic_string<CharT>(c_str);
+    }
+
+    CharT c_str[N+1];
+};
+
+template<typename CharT, std::size_t N>
+fixed_string(const CharT (&)[N])->fixed_string<CharT, N-1>;
+
+//  Other string utility functions.
+
+inline bool is_escaped(std::string_view s) {
+    return 
+        s.starts_with("\"") 
+        && s.ends_with("\"")
+        ;
+}
+
+inline bool string_to_int(std::string const& s, int& v, int base = 10) {
+    try {
+        v = stoi(s, nullptr, base);
+        return true;
+    }
+    catch (std::invalid_argument const&)
+    {
+        return false;
+    }
+    catch (std::out_of_range const&)
+    {
+        return false;
+    }
+}
+
+template<int Base = 10>
+inline std::string int_to_string(int i) {
+    if constexpr (8 == Base) {
+        std::ostringstream oss;
+        oss << std::oct << i;
+        return oss.str();
+    }
+    else if constexpr (10 == Base) {
+        return std::to_string(i);
+    }
+    else if constexpr (16 == Base) {
+        std::ostringstream oss;
+        oss << std::hex << i;
+        return oss.str();
+    }
+    else {
+        [] <bool flag = false>() {
+            static_assert(flag, "Unsupported int_to_string Base");
+        }();
+    }
+}
+
+inline char safe_toupper(char ch) {
+    return static_cast<char>(std::toupper(static_cast<unsigned char>(ch)));
+}
+
+inline char safe_tolower(char ch) {
+    return static_cast<char>(std::tolower(static_cast<unsigned char>(ch)));
+}
+
+inline std::string replace_all(
+    std::string        str, 
+    const std::string& from, 
+    const std::string& to
+)
+{
+    size_t start_pos = 0;
+    while((start_pos = str.find(from, start_pos)) != std::string::npos) {
+        str.replace(start_pos, from.length(), to);
+        start_pos += to.length();   // safe also when 'to' is a substring of 'from'
+    }
+    return str;
+}
+
+template<typename List>
+inline std::string join(List const& list) {
+    std::string r = "";
+    std::string sep = "";
+
+    for (auto const& cur : list) {
+        r += sep + cur;
+        sep = ", ";
+    }
+
+    return r;
+}
+
+} // namespace string_util
+
+
 //-----------------------------------------------------------------------
 //
 //  Conveniences for expressing Cpp1 references (rarely useful)