avoid redundant warnings

1 files changed, 11 insertions, 4 deletions

diff --git a/yapymake/makefile/__init__.py b/yapymake/makefile/__init__.py
index 1f4687c..e46179e 100644
--- a/yapymake/makefile/__init__.py
+++ b/yapymake/makefile/__init__.py
@@ -5,7 +5,7 @@ from pathlib import Path as ImpurePath, PurePath
 import re
 import subprocess
 import sys
-from typing import Dict, List, Optional, TextIO, Tuple
+from typing import Dict, List, Optional, Set, TextIO, Tuple, Any, Union
 
 from .token import *
 from ..args import Args
@@ -22,6 +22,7 @@ class Makefile:
     _targets: Dict[str, 'Target']
     first_non_special_target: Optional[str]
     args: Args
+    _warnings: Set[str]
 
     def __init__(self, args: Args):
         self._inference_rules = []
@@ -29,6 +30,7 @@ class Makefile:
         self._targets = dict()
         self.first_non_special_target = None
         self.args = args
+        self._warnings = set()
 
         if args.builtin_rules:
             self._inference_rules += BUILTIN_INFERENCE_RULES
@@ -66,6 +68,11 @@ class Makefile:
             *[str(x) for x in self._targets.values()],
         ])
 
+    def _warn(self, warning: str) -> None:
+        if warning not in self._warnings:
+            print(warning)
+            self._warnings.add(warning)
+
     def read(self, file: TextIO) -> None:
         lines_iter: PeekableIterator[str] = PeekableIterator(iter(file))
         for line in lines_iter:
@@ -98,7 +105,7 @@ class Makefile:
                 # > field is taken as the pathname.
                 # (GNU make will include each field separately, so let's do that here)
                 if len(fields) != 1:
-                    print('warning: non-POSIX multi-file include')
+                    self._warn('warning: non-POSIX multi-file include')
                 for included_file in fields:
                     # > The contents of the file specified by the pathname shall be read and processed as if they
                     # > appeared in the makefile in place of the include line.
@@ -277,8 +284,8 @@ class Makefile:
                         if ImpurePath(prerequisite_path).exists():
                             if name in self._targets:
                                 # we got here by following GNU
-                                print('warning: non-POSIX use of inference rule', f'{rule.s1}{rule.s2}',
-                                      'on explicit target', name)
+                                self._warn(f'warning: non-POSIX use of inference rule {rule.s1}{rule.s2} on explicit '
+                                           f'target {name}')
                             self._targets[name] = Target(name, [str(prerequisite_path)], rule.commands)
                             break
         if name not in self._targets: