[flang-commits] [PATCH] D119987: [flang] Allow tabs as white space in formats

[vdonaldson via Phabricator via flang-commits]

vdonaldson created this revision.
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The fortran standard views blanks in IO formats as white space in
non-string contexts.  Other compilers extend this to also view horizontal
tabs as white space.  Some compilers additionally add other white space
characters to this group.

Add recognition of horizontal and vertical tabs to runtime format
validation code to match what the runtime code currently does.


https://reviews.llvm.org/D119987

Files:
  flang/include/flang/Common/format.h
  flang/test/Semantics/io08.f90


Index: flang/test/Semantics/io08.f90
===================================================================
--- flang/test/Semantics/io08.f90
+++ flang/test/Semantics/io08.f90
@@ -37,6 +37,9 @@
   write(*,'($)')
   write(*,'(\)')
   write(*,'(RZ,RU,RP,RN,RD,RC,SS,SP,S,3G15.3e2)')
+  write(*, '(' // achar( 9) // ')') ! horizontal tab
+  write(*, '(' // achar(11) // ')') ! vertical tab
+  write(*, '(' // achar(32) // ')') ! space
 
   ! C1302 warnings; no errors
   write(*,'(3P7I2)')
Index: flang/include/flang/Common/format.h
===================================================================
--- flang/include/flang/Common/format.h
+++ flang/include/flang/Common/format.h
@@ -149,9 +149,20 @@
   int maxNesting_{0}; // max level of nested parentheses
 };
 
+template <typename CHAR> static inline bool IsWhite(CHAR c) {
+  // White space.  ' ' is standard.  Other characters are extensions.
+  // Extension candidates:
+  //   '\t' (horizontal tab)
+  //   '\n' (new line)
+  //   '\v' (vertical tab)
+  //   '\f' (form feed)
+  //   '\r' (carriage ret)
+  return c == ' ' || c == '\t' || c == '\v';
+}
+
 template <typename CHAR> CHAR FormatValidator<CHAR>::NextChar() {
   for (++cursor_; cursor_ < end_; ++cursor_) {
-    if (*cursor_ != ' ') {
+    if (!IsWhite(*cursor_)) {
       return toupper(*cursor_);
     }
   }
@@ -161,7 +172,7 @@
 
 template <typename CHAR> CHAR FormatValidator<CHAR>::LookAheadChar() {
   for (laCursor_ = cursor_ + 1; laCursor_ < end_; ++laCursor_) {
-    if (*laCursor_ != ' ') {
+    if (!IsWhite(*cursor_)) {
       return toupper(*laCursor_);
     }
   }


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