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authorZach White <skullydazed@users.noreply.github.com>2020-05-26 13:05:41 -0700
committerGitHub <noreply@github.com>2020-05-26 13:05:41 -0700
commit751316c34465ea77e066c3052729b207f3d62e0c (patch)
treecb99656b93c156757e2fd7c84fe716f9c300ca89 /lib/python/qmk/math.py
parent5d3bf8a050f3c0beb1f91147dc1ab54de36cbb05 (diff)
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[CLI] Add a subcommand for getting information about a keyboard (#8666)
You can now use `qmk info` to get information about keyboards and keymaps. Co-authored-by: Erovia <Erovia@users.noreply.github.com>
Diffstat (limited to 'lib/python/qmk/math.py')
-rw-r--r--lib/python/qmk/math.py33
1 files changed, 33 insertions, 0 deletions
diff --git a/lib/python/qmk/math.py b/lib/python/qmk/math.py
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+++ b/lib/python/qmk/math.py
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+"""Parse arbitrary math equations in a safe way.
+
+Gratefully copied from https://stackoverflow.com/a/9558001
+"""
+import ast
+import operator as op
+
+# supported operators
+operators = {ast.Add: op.add, ast.Sub: op.sub, ast.Mult: op.mul, ast.Div: op.truediv, ast.Pow: op.pow, ast.BitXor: op.xor, ast.USub: op.neg}
+
+
+def compute(expr):
+ """Parse a mathematical expression and return the answer.
+
+ >>> compute('2^6')
+ 4
+ >>> compute('2**6')
+ 64
+ >>> compute('1 + 2*3**(4^5) / (6 + -7)')
+ -5.0
+ """
+ return _eval(ast.parse(expr, mode='eval').body)
+
+
+def _eval(node):
+ if isinstance(node, ast.Num): # <number>
+ return node.n
+ elif isinstance(node, ast.BinOp): # <left> <operator> <right>
+ return operators[type(node.op)](_eval(node.left), _eval(node.right))
+ elif isinstance(node, ast.UnaryOp): # <operator> <operand> e.g., -1
+ return operators[type(node.op)](_eval(node.operand))
+ else:
+ raise TypeError(node)