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"""
@file
@brief One class which visits a syntax tree.
"""
import ast
import inspect
from .code_exception import CodeException
from .node_visitor_translator import CodeNodeVisitor
class TranslateClass:
"""
Interface for a class which translates a code
written in pseudo-SQL syntax into another language.
"""
def __init__(self, code_func):
"""
Constructor.
@param code_func code (str) or function(func)
"""
if isinstance(code_func, str):
code = code_func
else:
code = inspect.getsource(code_func)
self.init(code)
def init(self, code):
"""
Parses the function code and add it the class,
it complements the constructor.
@param code function code
"""
node = ast.parse(code)
v = CodeNodeVisitor()
v.visit(node)
self._rows = v.Rows
self._code = code
def __str__(self):
"""
Returns a string representing a tree.
"""
return self.to_str()
def to_str(self, fields=None):
"""
Returns a string representing a tree.
@param fields additional fields to add at the end of each row
@return string
"""
if fields is None:
fields = []
if len(fields) == 0:
rows = ["{0}{1}: {2} - nbch {3}".format(" " * r["indent"], r["type"], r["str"], len(r.get("children", [])))
for r in self._rows]
else:
rows = ["{0}{1}: {2} - nbch {3}".format(" " * r["indent"], r["type"], r["str"], len(r.get("children", [])))
+ " --- " + ",".join(["%s=%s" %
(_, r.get(_, "")) for _ in fields])
for r in self._rows]
return "\n".join(rows)
def Code(self):
"""
Returns the code of the initial Python function
into another language.
@return str
"""
# we add a field "processed" in each rows to tell it was interpreted
for row in self._rows:
row["processed"] = row["type"] == "Module"
code_rows = []
for row in self._rows:
if row["processed"]:
continue
if row["type"] == "FunctionDef":
res = self.interpretFunction(row)
if res is not None and len(res) > 0:
code_rows.extend(res)
for row in self._rows:
if not row["processed"]:
return self.RaiseCodeException(
"the function was unable to interpret all the lines",
code_rows=code_rows)
return "\n".join(code_rows)
def RaiseCodeException(self, message, field="processed", code_rows=None):
"""
Raises an exception when interpreting the code.
@param field field to add to the message exception
@param code_rows list of rows to display
:raises: CodeException
"""
if code_rows is None:
code_rows = []
if len(code_rows) > 0:
if "_status" in self.__dict__ and len(self._status) > 0:
code_rows = code_rows + ["", "-- STATUS --", ""] + self._status
raise CodeException(message + "\n---tree:\n"
+ self.to_str(["processed"]) + "\n\n---so far:\n"
+ "\n".join(code_rows))
elif "_status" in self.__dict__:
raise CodeException(message + "\n---tree:\n"
+ self.to_str(["processed"]) + "\n\n-- STATUS --\n"
+ "\n".join(self._status))
else:
raise CodeException(message + "\n---tree:\n"
+ self.to_str(["processed"]))
def interpretFunction(self, obj):
"""
Starts the interpretation of node which begins a function.
@param obj obj to begin with (a function)
@return list of strings
"""
if "children" not in obj:
return self.RaiseCodeException("children key is missing")
if "name" not in obj:
return self.RaiseCodeException("name is missing")
obj["processed"] = True
chil = obj["children"]
code_rows = []
# signature
name = obj["name"]
argus = [_ for _ in chil if _["type"] == "arguments"]
args = []
for a in argus:
a["processed"] = True
for ch in a["children"]:
if ch["type"] == "arg":
ch["processed"] = True
args.append(ch)
names = [_["str"] for _ in args]
sign = self.Signature(name, names)
if sign is not None and len(sign) > 0:
code_rows.extend(sign)
# the rest
self._status = code_rows # for debugging purpose
# assi = [_ for _ in chil if _["type"] == "Assign"]
for an in chil:
if an["type"] == "Assign":
one = self.Intruction(an)
if one is not None and len(one) > 0:
code_rows.extend(one)
elif an["type"] == "Return":
one = self.interpretReturn(an)
if one is not None and len(one) > 0:
code_rows.extend(one)
elif an["type"] == "arguments":
pass
else:
return self.RaiseCodeException("unexpected type: " + an["type"])
return code_rows
def Signature(self, name, rows):
"""
Build the signature of a function based on its name and its children.
@param name name
@param rows node where type == arguments
@return list of strings (code)
"""
return self.RaiseCodeException("not implemented")
def Intruction(self, rows):
"""
Builds an instruction of a function based on its name and its children.
@param rows node where type == Assign
@return list of strings (code)
"""
rows["processed"] = True
chil = rows["children"]
name = [_ for _ in chil if _["type"] == "Name"]
if len(name) != 1:
return self.RaiseCodeException(
"expecting only one row not %d" %
len(chil))
call = [_ for _ in chil if _["type"] == "Call"]
if len(call) != 1:
return self.RaiseCodeException(
"expecting only one row not %d" %
len(call))
name = name[0]
name["processed"] = True
call = call[0]
call["processed"] = True
varn = name["str"]
kind = call["str"]
# the first attribute gives the name the table
method = call["children"][0]
method["processed"] = True
table, meth = method["str"].split(".")
if meth != kind:
return self.RaiseCodeException(
"cannot go further, expects: {0}=={1}".format(
kind,
meth))
if kind == "select":
top = call["children"][1:]
return self.Select(varn, table, top)
elif kind == "where":
top = call["children"][1:]
return self.Where(varn, table, top)
elif kind == "groupby":
top = call["children"][1:]
return self.GroupBy(varn, table, top)
else:
return self.RaiseCodeException("not implemented for: " + kind)
def Select(self, name, table, rows):
"""
Interprets a select statement.
@param name name of the table which receives the results
@param table name of the table it applies to
@param rows rows to consider
@return list of strings (code)
"""
return self.RaiseCodeException("not implemented")
def Where(self, name, table, rows):
"""
Interprets a select statement.
@param name name of the table which receives the results
@param table name of the table it applies to
@param rows rows to consider
@return list of strings (code)
"""
return self.RaiseCodeException("not implemented")
_symbols = {"Lt": "<", "Gt": ">", "Mult": "*", }
def ResolveExpression(self, node, prefixAtt):
"""
Produces an expression based on a a node and its children.
@param node node
@param prefixAtt prefix to add before an attribute (usually _)
@return a string, the used fields, the called functions
"""
if node["type"] == "keyword":
chil = node["children"]
if len(chil) == 1:
node["processed"] = True
return self.ResolveExpression(chil[0], prefixAtt)
else:
return self.RaiseCodeException(
"not implemented for type: "
+ node["type"])
elif node["type"] == "BinOp" or node["type"] == "Compare":
chil = node["children"]
if len(chil) == 3:
node["processed"] = True
ex1, fi1, fu1 = self.ResolveExpression(chil[0], prefixAtt)
ex2, fi2, fu2 = self.ResolveExpression(chil[1], prefixAtt)
ex3, fi3, fu3 = self.ResolveExpression(chil[2], prefixAtt)
fi1.update(fi2)
fi1.update(fi3)
fu1.update(fu2)
fu1.update(fu3)
ex = "{0}{1}{2}".format(ex1, ex2, ex3)
return ex, fi1, fu1
else:
return self.RaiseCodeException(
"not implemented for type: "
+ node["type"])
elif node["type"] in TranslateClass._symbols:
node["processed"] = True
return TranslateClass._symbols[node["type"]], {}, {}
elif node["type"] == "Attribute":
node["processed"] = True
return prefixAtt + node["str"], {node["str"]: node}, {}
elif node["type"] == "Num":
node["processed"] = True
return node["str"], {}, {}
elif node["type"] == "Call":
node["processed"] = True
expre = []
field = {}
funcs = {}
if node["str"] in ["Or", "And", "Not"]:
for chil in node["children"]:
if chil["type"] == "Attribute":
if chil["str"] != node["str"]:
return self.RaiseCodeException("incoherence")
elif len(chil["children"]) != 1:
return self.RaiseCodeException("incoherence")
else:
chil["processed"] = True
ex, fi, fu = self.ResolveExpression(
chil["children"][0], prefixAtt)
expre.append("({0})".format(ex))
field.update(fi)
funcs.update(funcs)
expre.append(node["str"].lower())
else:
ex, fi, fu = self.ResolveExpression(chil, prefixAtt)
expre.append("({0})".format(ex))
field.update(fi)
funcs.update(funcs)
elif node["str"] == "CFT":
# we need to look further as CFT is a way to call a function
funcName = None
subexp = []
for chil in node["children"]:
if chil["type"] == "Attribute":
chil["processed"] = True
ex, fi, fu = self.ResolveExpression(chil, prefixAtt)
subexp.append(ex)
field.update(fi)
funcs.update(funcs)
elif chil["type"] == "Name" and chil["str"] == "CFT":
pass
elif chil["type"] == "Name":
# we call function chil["str"]
funcName = chil["str"]
funcs[chil["str"]] = chil["str"]
else:
return self.RaiseCodeException(
"unexpected configuration: "
+ node["type"])
chil["processed"] = True
expre.append("{0}({1})".format(funcName, ",".join(subexp)))
elif node["str"] == "len":
# aggregated function
funcName = None
subexp = []
for chil in node["children"]:
if chil["type"] == "Attribute":
chil["processed"] = True
ex, fi, fu = self.ResolveExpression(chil, prefixAtt)
subexp.append(ex)
field.update(fi)
funcs.update(funcs)
elif chil["type"] == "Name" and chil["str"] == "CFT":
pass
elif chil["type"] == "Name":
# we call function chil["str"]
funcName = chil["str"]
funcs[chil["str"]] = chil["str"]
else:
return self.RaiseCodeException(
"unexpected configuration: "
+ node["type"])
chil["processed"] = True
expre.append("{0}({1})".format(funcName, ",".join(subexp)))
else:
return self.RaiseCodeException(
"not implemented for function: "
+ node["str"])
return " ".join(expre), field, funcs
else:
return self.RaiseCodeException(
"not implemented for type: "
+ node["type"])
def interpretReturn(self, obj):
"""
Starts the interpretation of a node which sets a return.
@param obj obj to begin with (a function)
@return list of strings
"""
if "children" not in obj:
return self.RaiseCodeException("children key is missing")
allret = []
obj["processed"] = True
for node in obj["children"]:
if node["type"] == "Name":
allret.append(node)
else:
return self.RaiseCodeException("unexpected type: " + node["type"])
return self.setReturn(allret)
def setReturn(self, nodes):
"""
Indicates all nodes containing information about returned results.
@param node list of nodes
@return list of string
"""
return self.RaiseCodeException("not implemented")
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