From d90fcb4048f720a238cbb350164ec8f63d1eec60 Mon Sep 17 00:00:00 2001
From: Jussi Pakkanen <jpakkane@gmail.com>
Date: Sun, 19 Jun 2016 21:56:09 +0300
Subject: Created ternary operator. Closes #538.

---
 mesonbuild/interpreter.py | 12 ++++++++++++
 mesonbuild/mparser.py     | 14 ++++++++++++++
 2 files changed, 26 insertions(+)

(limited to 'mesonbuild')

diff --git a/mesonbuild/interpreter.py b/mesonbuild/interpreter.py
index 5201be2..fddc3c0 100644
--- a/mesonbuild/interpreter.py
+++ b/mesonbuild/interpreter.py
@@ -1323,6 +1323,8 @@ class Interpreter():
             return self.evaluate_plusassign(cur)
         elif isinstance(cur, mparser.IndexNode):
             return self.evaluate_indexing(cur)
+        elif isinstance(cur, mparser.TernaryNode):
+            return self.evaluate_ternary(cur)
         elif self.is_elementary_type(cur):
             return cur
         else:
@@ -2401,6 +2403,16 @@ class Interpreter():
         if not isinstance(node.elseblock, mparser.EmptyNode):
             self.evaluate_codeblock(node.elseblock)
 
+    def evaluate_ternary(self, node):
+        assert(isinstance(node, mparser.TernaryNode))
+        result = self.evaluate_statement(node.condition)
+        if not isinstance(result, bool):
+            raise InterpreterException('Ternary condition is not boolean.')
+        if result:
+            return self.evaluate_statement(node.trueblock)
+        else:
+            return self.evaluate_statement(node.falseblock)
+
     def evaluate_foreach(self, node):
         assert(isinstance(node, mparser.ForeachClauseNode))
         varname = node.varname.value
diff --git a/mesonbuild/mparser.py b/mesonbuild/mparser.py
index fd720fb..b3fdba8 100644
--- a/mesonbuild/mparser.py
+++ b/mesonbuild/mparser.py
@@ -67,6 +67,7 @@ class Lexer:
             ('lt', re.compile(r'<')),
             ('ge', re.compile(r'>=')),
             ('gt', re.compile(r'>')),
+            ('questionmark', re.compile(r'\?')),
         ]
 
     def lex(self, code):
@@ -282,6 +283,14 @@ class IfNode():
         self.condition = condition
         self.block = block
 
+class TernaryNode():
+    def __init__(self, lineno, colno, condition, trueblock, falseblock):
+        self.lineno = lineno
+        self.colno = colno
+        self.condition = condition
+        self.trueblock = trueblock
+        self.falseblock = falseblock
+
 class ArgumentNode():
     def __init__(self, token):
         self.lineno = token.lineno
@@ -383,6 +392,11 @@ class Parser:
                 raise ParseException('Assignment target must be an id.',
                                      left.lineno, left.colno)
             return AssignmentNode(left.lineno, left.colno, left.value, value)
+        elif self.accept('questionmark'):
+            trueblock = self.e1()
+            self.expect('colon')
+            falseblock = self.e1()
+            return TernaryNode(left.lineno, left.colno, left, trueblock, falseblock)
         return left
 
     def e2(self):
-- 
cgit v1.1


From b382abdd2c307d0716353013022df5039991ac1f Mon Sep 17 00:00:00 2001
From: Jussi Pakkanen <jpakkane@gmail.com>
Date: Sun, 19 Jun 2016 22:02:59 +0300
Subject: Forbid nested ternary operations.

---
 mesonbuild/mparser.py | 6 ++++++
 1 file changed, 6 insertions(+)

(limited to 'mesonbuild')

diff --git a/mesonbuild/mparser.py b/mesonbuild/mparser.py
index b3fdba8..2f0eb2d 100644
--- a/mesonbuild/mparser.py
+++ b/mesonbuild/mparser.py
@@ -353,6 +353,7 @@ class Parser:
     def __init__(self, code):
         self.stream = Lexer().lex(code)
         self.getsym()
+        self.in_ternary = False
 
     def getsym(self):
         try:
@@ -393,9 +394,14 @@ class Parser:
                                      left.lineno, left.colno)
             return AssignmentNode(left.lineno, left.colno, left.value, value)
         elif self.accept('questionmark'):
+            if self.in_ternary:
+                raise ParseException('Nested ternary operators are not allowed.',
+                                     left.lineno, left.colno)
+            self.in_ternary = True
             trueblock = self.e1()
             self.expect('colon')
             falseblock = self.e1()
+            self.in_ternary = False
             return TernaryNode(left.lineno, left.colno, left, trueblock, falseblock)
         return left
 
-- 
cgit v1.1