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85 lines
3.3 KiB
85 lines
3.3 KiB
from engine.ast import TableInfo, ast_node, Context, include
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from engine.join import join
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from engine.expr import expr
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from engine.scan import filter
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from engine.utils import base62uuid
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class projection(ast_node):
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name='select'
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def __init__(self, parent:ast_node, node, context:Context = None, outname = None, disp = True):
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self.disp = disp
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self.outname = outname
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ast_node.__init__(self, parent, node, context)
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def init(self, _):
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if self.outname is None:
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self.outname = self.context.gen_tmptable()
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def produce(self, node):
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p = node['select']
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self.projections = p if type(p) is list else [p]
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print(node)
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def spawn(self, node):
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self.datasource = None
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if 'from' in node:
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from_clause = node['from']
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if type(from_clause) is list:
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# from joins
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join(self, from_clause)
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elif type(from_clause) is dict:
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if 'value' in from_clause:
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value = from_clause['value']
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if type(value) is dict:
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if 'select' in value:
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# from subquery
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projection(self, from_clause, disp = False)
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else:
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# TODO: from func over table
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print(f"from func over table{node}")
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elif type(value) is str:
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self.datasource = self.context.tables_byname[value]
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if 'assumptions' in from_clause:
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ord = from_clause['assumptions']['ord'] == 'asc'
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ord = '^' if ord else '|^'
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# TODO: generate view of table by order
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elif type(from_clause) is str:
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self.datasource = self.context.tables_byname[from_clause]
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if self.datasource is None:
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raise ValueError('spawn error: from clause')
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if self.datasource is not None:
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self.datasource_changed = True
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self.prev_datasource = self.context.datasource
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self.context.datasource = self.datasource
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if 'where' in node:
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self.datasource = filter(self, node['where'], True).output
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self.context.datasource = self.datasource
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def consume(self, _):
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disp_varname = 'd'+base62uuid(7)
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self.emit_no_ln(f'{disp_varname}:(')
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for i, proj in enumerate(self.projections):
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if type(proj) is dict:
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if 'value' in proj:
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e = proj['value']
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if type(e) is str:
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self.emit_no_ln(f"{self.datasource.parse_tablenames(proj['value'])}")
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elif type(e) is dict:
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self.emit_no_ln(f"{expr(self, e).k9expr}")
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self.emit_no_ln(';'if i < len(self.projections)-1 else '')
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self.emit(')')
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if self.disp:
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if len(self.projections) > 1:
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self.emit(f'+{disp_varname}')
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else:
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self.emit(f'+,(,{disp_varname})')
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if self.datasource_changed:
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self.context.datasource = self.prev_datasource
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import sys
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include(sys.modules[__name__]) |