diff options
Diffstat (limited to 'comm/third_party/python/fluent.migratetb/fluent/migratetb/evaluator.py')
-rw-r--r-- | comm/third_party/python/fluent.migratetb/fluent/migratetb/evaluator.py | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/comm/third_party/python/fluent.migratetb/fluent/migratetb/evaluator.py b/comm/third_party/python/fluent.migratetb/fluent/migratetb/evaluator.py new file mode 100644 index 0000000000..90c626f933 --- /dev/null +++ b/comm/third_party/python/fluent.migratetb/fluent/migratetb/evaluator.py @@ -0,0 +1,28 @@ +from fluent.syntax import ast as FTL +from fluent.syntax.visitor import Transformer + +from .transforms import Transform + + +class Evaluator(Transformer): + """An AST transformer for evaluating migration Transforms. + + An AST transformer (i.e. a visitor capable of modifying the AST) which + walks an AST hierarchy and evaluates nodes which are migration Transforms. + """ + + def __init__(self, ctx): + self.ctx = ctx + + def visit(self, node): + if not isinstance(node, FTL.BaseNode): + return node + + if isinstance(node, Transform): + # Some transforms don't expect other transforms as children. + # Evaluate the children first. + transform = self.generic_visit(node) + # Then, evaluate this transform. + return transform(self.ctx) + + return self.generic_visit(node) |