You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
AQuery/engine/projection.py

74 lines
2.7 KiB

from engine.ast import TableInfo, ast_node, Context, include
from engine.join import join
from engine.expr import expr
from engine.utils import base62uuid
class projection(ast_node):
name='select'
def __init__(self, parent:ast_node, node, context:Context = None, outname = None, disp = True):
self.disp = disp
self.outname = outname
ast_node.__init__(self, parent, node, context)
def init(self, _):
if self.outname is None:
self.outname = self.context.gen_tmptable()
def produce(self, node):
p = node['select']
self.projections = p if type(projection) == list else [p]
print(node)
def spawn(self, node):
self.datasource = None
if 'from' in node:
from_clause = node['from']
if type(from_clause) is list:
# from joins
join(self, from_clause)
elif type(from_clause) is dict:
if 'value' in from_clause:
value = from_clause['value']
if type(value) is dict:
if 'select' in value:
# from subquery
projection(self, from_clause, disp = False)
else:
# TODO: from func over table
print(f"from func over table{node}")
elif type(value) is str:
self.datasource = self.context.tables_byname[value]
if 'assumptions' in from_clause:
ord = from_clause['assumptions']['ord'] == 'asc'
ord = '^' if ord else '|^'
# TODO: generate view of table by order
elif type(from_clause) is str:
self.datasource = self.context.tables_byname[from_clause]
if self.datasource is None:
raise ValueError('spawn error: from clause')
3 years ago
if 'where' in node:
# apply filter
pass
def consume(self, node):
disp_varname = 'disptmp' + base62uuid()
self.emit_no_ln(f'{disp_varname}:(')
for proj in self.projections:
if type(proj) is dict:
if 'value' in proj:
e = proj['value']
if type(e) is str:
self.emit_no_ln(f"{self.datasource.parse_tablenames(proj['value'])};")
elif type(e) is dict:
self.emit_no_ln(f"{expr(self, e).k9expr};")
self.emit(')')
if self.disp:
self.emit(disp_varname)
import sys
include(sys.modules[__name__])