[flang][runtime] Extension: allow a comma to terminate a fixed input … (#76768)

…field

When a comma appears in a fixed-width input field for integer editing,
many compilers accept it without error and interpret the comma as
terminating the field early.

2 files changed, 9 insertions, 2 deletions

diff --git a/flang/docs/Extensions.md b/flang/docs/Extensions.md
index 02ccd51..9868907 100644
--- a/flang/docs/Extensions.md
+++ b/flang/docs/Extensions.md
@@ -318,6 +318,8 @@ end
 * A `NAMELIST` input group may omit its trailing `/` character if
   it is followed by another `NAMELIST` input group.
 * A `NAMELIST` input group may begin with either `&` or `$`.
+* A comma in a fixed-width numeric input field terminates the
+  field rather than signaling an invalid character error.
 
 ### Extensions supported when enabled by options
 
diff --git a/flang/runtime/edit-input.cpp b/flang/runtime/edit-input.cpp
index 71e7f4e..6bffe24 100644
--- a/flang/runtime/edit-input.cpp
+++ b/flang/runtime/edit-input.cpp
@@ -80,6 +80,8 @@ static bool EditBOZInput(
     } else if (LOG2_BASE >= 4 && ch >= '8' && ch <= '9') {
     } else if (LOG2_BASE >= 4 && ch >= 'A' && ch <= 'F') {
     } else if (LOG2_BASE >= 4 && ch >= 'a' && ch <= 'f') {
+    } else if (ch == ',') {
+      break; // end non-list-directed field early
     } else {
       io.GetIoErrorHandler().SignalError(
           "Bad character '%lc' in B/O/Z input field", ch);
@@ -214,6 +216,8 @@ bool EditIntegerInput(
     int digit{0};
     if (ch >= '0' && ch <= '9') {
       digit = ch - '0';
+    } else if (ch == ',') {
+      break; // end non-list-directed field early
     } else {
       io.GetIoErrorHandler().SignalError(
           "Bad character '%lc' in INTEGER input field", ch);
@@ -291,7 +295,8 @@ static ScannedRealInput ScanRealInput(
   }
   bool bzMode{(edit.modes.editingFlags & blankZero) != 0};
   int exponent{0};
-  if (!next || (!bzMode && *next == ' ')) {
+  if (!next || (!bzMode && *next == ' ') ||
+      (!(edit.modes.editingFlags & decimalComma) && *next == ',')) {
     if (!edit.IsListDirected() && !io.GetConnectionState().IsAtEOF()) {
       // An empty/blank field means zero when not list-directed.
       // A fixed-width field containing only a sign is also zero;
@@ -473,7 +478,7 @@ static ScannedRealInput ScanRealInput(
     while (next && (*next == ' ' || *next == '\t')) {
       next = io.NextInField(remaining, edit);
     }
-    if (next) {
+    if (next && (*next != ',' || (edit.modes.editingFlags & decimalComma))) {
       return {}; // error: unused nonblank character in fixed-width field
     }
   }