From a816e1c1fa2f70440e82b96eb027588c60de918b Mon Sep 17 00:00:00 2001
From: Xavier Claessens <xavier.claessens@collabora.com>
Date: Tue, 17 Jul 2018 16:47:41 -0400
Subject: [PATCH] Interpreter: Add 'continue' and 'break' keywords

Closes: #3601
---
 mesonbuild/interpreterbase.py            | 24 ++++++++++++++++++++++--
 mesonbuild/mparser.py                    | 14 ++++++++++++--
 test cases/common/64 foreach/meson.build | 13 +++++++++++++
 3 files changed, 47 insertions(+), 4 deletions(-)

diff --git a/mesonbuild/interpreterbase.py b/mesonbuild/interpreterbase.py
index 22bb95bd4..c0064ab0d 100644
--- a/mesonbuild/interpreterbase.py
+++ b/mesonbuild/interpreterbase.py
@@ -300,6 +300,12 @@ class InvalidArguments(InterpreterException):
 class SubdirDoneRequest(BaseException):
     pass
 
+class ContinueRequest(BaseException):
+    pass
+
+class BreakRequest(BaseException):
+    pass
+
 class InterpreterObject:
     def __init__(self):
         self.methods = {}
@@ -453,6 +459,10 @@ class InterpreterBase:
             return self.evaluate_indexing(cur)
         elif isinstance(cur, mparser.TernaryNode):
             return self.evaluate_ternary(cur)
+        elif isinstance(cur, mparser.ContinueNode):
+            raise ContinueRequest()
+        elif isinstance(cur, mparser.BreakNode):
+            raise BreakRequest()
         elif self.is_elementary_type(cur):
             return cur
         else:
@@ -641,7 +651,12 @@ The result of this is undefined and will become a hard error in a future Meson r
                 return items
             for item in items:
                 self.set_variable(varname, item)
-                self.evaluate_codeblock(node.block)
+                try:
+                    self.evaluate_codeblock(node.block)
+                except ContinueRequest:
+                    continue
+                except BreakRequest:
+                    break
         elif isinstance(items, dict):
             if len(node.varnames) != 2:
                 raise InvalidArguments('Foreach on dict unpacks key and value')
@@ -650,7 +665,12 @@ The result of this is undefined and will become a hard error in a future Meson r
             for key, value in items.items():
                 self.set_variable(node.varnames[0].value, key)
                 self.set_variable(node.varnames[1].value, value)
-                self.evaluate_codeblock(node.block)
+                try:
+                    self.evaluate_codeblock(node.block)
+                except ContinueRequest:
+                    continue
+                except BreakRequest:
+                    break
         else:
             raise InvalidArguments('Items of foreach loop must be an array or a dict')
 
diff --git a/mesonbuild/mparser.py b/mesonbuild/mparser.py
index 429f0146a..be5c807c4 100644
--- a/mesonbuild/mparser.py
+++ b/mesonbuild/mparser.py
@@ -91,8 +91,8 @@ class Lexer:
         self.code = code
         self.keywords = {'true', 'false', 'if', 'else', 'elif',
                          'endif', 'and', 'or', 'not', 'foreach', 'endforeach',
-                         'in'}
-        self.future_keywords = {'continue', 'break', 'return'}
+                         'in', 'continue', 'break'}
+        self.future_keywords = {'return'}
         self.token_specification = [
             # Need to be sorted longest to shortest.
             ('ignore', re.compile(r'[ \t]')),
@@ -243,6 +243,12 @@ class StringNode(ElementaryNode):
     def __str__(self):
         return "String node: '%s' (%d, %d)." % (self.value, self.lineno, self.colno)
 
+class ContinueNode(ElementaryNode):
+    pass
+
+class BreakNode(ElementaryNode):
+    pass
+
 class ArrayNode:
     def __init__(self, args):
         self.subdir = args.subdir
@@ -759,6 +765,10 @@ class Parser:
             block = self.foreachblock()
             self.block_expect('endforeach', block_start)
             return block
+        if self.accept('continue'):
+            return ContinueNode(self.current)
+        if self.accept('break'):
+            return BreakNode(self.current)
         return self.statement()
 
     def codeblock(self):
diff --git a/test cases/common/64 foreach/meson.build b/test cases/common/64 foreach/meson.build
index e633de887..7084e8003 100644
--- a/test cases/common/64 foreach/meson.build	
+++ b/test cases/common/64 foreach/meson.build	
@@ -18,3 +18,16 @@ foreach i : tests
   # we definitely don't want that.
   tests = ['test4', 'prog4', 'prog4.c']
 endforeach
+
+items = ['a', 'continue', 'b', 'break', 'c']
+result = []
+foreach i : items
+  if i == 'continue'
+    continue
+  elif i == 'break'
+    break
+  endif
+  result += i
+endforeach
+
+assert(result == ['a', 'b'], 'Continue or break in foreach failed')