Handle then unary negation operator.

interpreter.py

@@ -945,6 +945,8 @@ class Interpreter():
             return self.evaluate_orstatement(cur)
         elif isinstance(cur, mparser.NotNode):
             return self.evaluate_notstatement(cur)
+        elif isinstance(cur, mparser.UMinusNode):
+            return self.evaluate_uminusstatement(cur)
         elif isinstance(cur, mparser.ArithmeticNode):
             return self.evaluate_arithmeticstatement(cur)
         elif isinstance(cur, mparser.ForeachClauseNode):
@@ -1791,6 +1793,14 @@ class Interpreter():
             raise InterpreterException('Argument to "not" is not a boolean.')
         return not v
 
+    def evaluate_uminusstatement(self, cur):
+        v = self.evaluate_statement(cur.value)
+        if isinstance(v, mparser.NumberNode):
+            v = v.value
+        if not isinstance(v, int):
+            raise InterpreterException('Argument to negation is not an integer.')
+        return -v
+
     def evaluate_arithmeticstatement(self, cur):
         l = self.to_native(self.evaluate_statement(cur.left))
         r = self.to_native(self.evaluate_statement(cur.right))

mparser.py

@@ -41,7 +41,7 @@ class Lexer:
             # Need to be sorted longest to shortest.
             ('ignore', re.compile(r'[ \t]')),
             ('id', re.compile('[_a-zA-Z][_0-9a-zA-Z]*')),
-            ('number', re.compile(r'-?\d+')),
+            ('number', re.compile(r'\d+')),
             ('eol_cont', re.compile(r'\\\n')),
             ('eol', re.compile(r'\n')),
             ('multiline_string', re.compile(r"'''(.|\n)*?'''", re.M)),
@@ -114,6 +114,7 @@ class Lexer:
                         else:
                             value = match_text
                     yield Token(tid, curline, col, value)
+                    break
             if not matched:
                 raise ParseException('lexer', lineno, col)
 
@@ -245,6 +246,12 @@ class IfClauseNode():
         self.ifs = []
         self.elseblock = EmptyNode()
 
+class UMinusNode():
+    def __init__(self, lineno, colno, value):
+        self.lineno = lineno
+        self.colno = colno
+        self.value = value
+
 class IfNode():
     def __init__(self, lineno, colno, condition, block):
         self.lineno = lineno
@@ -392,6 +399,8 @@ class Parser:
     def e6(self):
         if self.accept('not'):
             return NotNode(self.current.lineno, self.current.colno, self.e7())
+        if self.accept('dash'):
+            return UMinusNode(self.current.lineno, self.current.colno, self.e7())
         return self.e7()
 
     def e7(self):

test cases/common/59 object generator/meson.build

@@ -12,7 +12,7 @@ else
   outputname = '@BASENAME@.o'
 endif
 
-cc = meson.get_compiler('c').cmd_array().get(0-1)
+cc = meson.get_compiler('c').cmd_array().get(-1)
 # Generate an object file manually.
 gen = generator(python,
  output : outputname,