[flang] Extension: allow tabs in output format strings
A CHARACTER variable used as an output format may contain
unquoted tab characters, which are treated as if they had
been quoted. This is an extension supported by all other
Fortran compilers to which I have access.
Differential Revision: https://reviews.llvm.org/D112350
GitOrigin-RevId: fbb020fb48be454da35c77798dc63fd3304c0b80
diff --git a/docs/Extensions.md b/docs/Extensions.md
index 67a087d..02276fb 100644
--- a/docs/Extensions.md
+++ b/docs/Extensions.md
@@ -122,6 +122,7 @@
files are easier to write and use.
* $ and \ edit descriptors are supported in FORMAT to suppress newline
output on user prompts.
+* Tabs in format strings (not `FORMAT` statements) are allowed on output.
* REAL and DOUBLE PRECISION variable and bounds in DO loops
* Integer literals without explicit kind specifiers that are out of range
for the default kind of INTEGER are assumed to have the least larger kind
diff --git a/runtime/format-implementation.h b/runtime/format-implementation.h
index b0ebcbc..a32bb8e 100644
--- a/runtime/format-implementation.h
+++ b/runtime/format-implementation.h
@@ -359,6 +359,10 @@
context.AdvanceRecord(repeat && *repeat > 0 ? *repeat : 1);
} else if (ch == '$' || ch == '\\') {
context.mutableModes().nonAdvancing = true;
+ } else if (ch == '\t' || ch == '\v') {
+ // Tabs (extension)
+ // TODO: any other raw characters?
+ context.Emit(format_ + offset_ - 1, 1);
} else {
context.SignalError(IostatErrorInFormat,
"Invalid character '%c' in FORMAT", static_cast<char>(ch));
