gavo.svcs.vizierexprs module

Classes and methods to support vizier-type specifications on fields.

class gavo.svcs.vizierexprs.DateFlattener

Bases: _Flattener

A _Flattener producing SQL for data-like columns.

This is supposed to work for timestamp-valued and MJD-valued columns alike. The difference is handled on the level of nodes (DateNode vs. MJDNode).

class gavo.svcs.vizierexprs.DateNode(children, operator)

Bases: ParseNode

A node containing date operands (datetime objects, as a rule).

As an extension to VizieR, we interpret floats as well, where 1000 .. 3000 is a julian year, 10000 … 100000 is an MJD and 2000000 .. 4000000 is a JD.

class gavo.svcs.vizierexprs.MJDNode(children, operator)

Bases: DateNode

getSQLKey(name, item, sqlPars)

wraps base.getSQLKey and can be overridden in case operand mangling is necessary.

Do not call base.getSQLKey directly from within ParseNodes.

class gavo.svcs.vizierexprs.NumericFlattener

Bases: _Flattener

A _Flattener for float- and int-valued columns.

class gavo.svcs.vizierexprs.NumericIntervalFlattener

Bases: NumericFlattener

A _Flattener for matching against min/max pairs of columns.

Here, field is this (min_column, max_column) pair.

This currently isn’t used anywhere in DaCHS itself. You can use it in custom phraseMakers, though; cf. obsform/q

class gavo.svcs.vizierexprs.NumericNode(children, operator)

Bases: ParseNode

A node containing numeric operands (floats or dates).

class gavo.svcs.vizierexprs.ParseNode(children, operator)

Bases: object

is a parse node, consisting of an operator and children.

The parse trees returned by the various parse functions are built from these.

This is an abstract class.

getSQLKey(name, item, sqlPars)

wraps base.getSQLKey and can be overridden in case operand mangling is necessary.

Do not call base.getSQLKey directly from within ParseNodes.

insertChild(index, field, sqlPars)

inserts children[index] into sqlPars with a unique key and returns the key.

children[index] must be atomic (i.e., no ParseNode).

class gavo.svcs.vizierexprs.StringFlattener

Bases: _Flattener

A _Flattener turning String-like Vizier expressions into SQL conditions against string-valued columns.

getSQLFor(node, field, sqlPars)

returns SQL for a parse node node over an InputKey field.

sqlPars is the dict that is later passed to conn.execute and will be modified here.

class gavo.svcs.vizierexprs.StringNode(children, operator)

Bases: ParseNode

A node containing string operands.

class gavo.svcs.vizierexprs.ToVexprConverter

Bases: FromSQLConverter

mapComplex(sqlType, length)

simpleMap = {'bigint': 'vexpr-float', 'char': 'vexpr-string', 'date': 'vexpr-date', 'double': 'vexpr-float', 'double precision': 'vexpr-float', 'float': 'vexpr-float', 'int': 'vexpr-float', 'integer': 'vexpr-float', 'real': 'vexpr-float', 'smallint': 'vexpr-float', 'text': 'vexpr-string', 'timestamp': 'vexpr-date', 'unicode': 'vexpr-string', 'vexpr-date': 'vexpr-date', 'vexpr-float': 'vexpr-float', 'vexpr-string': 'vexpr-string'}

typeSystem = 'vizierexpr'

gavo.svcs.vizierexprs.adaptInputKey(inputKey)

returns ik changed to generate SQL for Vizier-like expressions.

This is used for buildFrom on CondDescs and renderers having parameterStyle form.

gavo.svcs.vizierexprs.format_placeholder(min_val, max_val, formatter)

returns a placeholder string for a possibly open interval.

*_val may be None, formatter has to accept a non-None value and return the proper representation for the placeholder string.

If no placeholder can be generated, this function returns None.

gavo.svcs.vizierexprs.getComplexGrammar(baseLiteral, pmBuilder, errorLiteral=None, nodeClass=<class 'gavo.svcs.vizierexprs.NumericNode'>)

returns the root element of a grammar parsing numeric vizier-like expressions.

This is used for both dates and floats, use baseLiteral to match the operand terminal. The trouble with dates is that the +/- operator has a simple float as the second operand, and that’s why you can pass in an errorLiteral and and pmBuilder.

gavo.svcs.vizierexprs.getPlaceholderFor(inputKey, values)

returns a placeholder (suggested input) for inputKey, where values is the original values element.

This will currently be None unless we do a numeric input.

gavo.svcs.vizierexprs.getStringGrammar()

returns a grammar for parsing vizier-like string expressions.

gavo.svcs.vizierexprs.makeConeSearchFor(inputKey)

returns an //scs#makeSpointCD condDesc tailored for inputKey.

gavo.svcs.vizierexprs.makeDatePmNode(s, loc, toks)

returns a +/- node for dates, i.e., toks[1] is a float in days.

gavo.svcs.vizierexprs.makeMJDPmNode(s, loc, toks)

returns a +/- node for MJDs, i.e., toks[1] is a float in days, and an MJDNode must be returned.

gavo.svcs.vizierexprs.makePmNode(s, loc, toks)

gavo.svcs.vizierexprs.parseDateExpr(str, baseSymbol={expr StringEnd})

returns a parse tree for vizier-like expressions over ISO dates.

Note that the semantic validity of the date (like, month<13) is not checked by the grammar.

gavo.svcs.vizierexprs.parseDateExprToMJD(str, baseSymbol={expr StringEnd})

returns a parse tree for vizier-like expression of ISO dates with parsed values in MJD.

gavo.svcs.vizierexprs.parseDateTime(s, pos, tok)

returns a datetime from a date/time spec.

This can be an ISO string or a julian year, JD, or MJD by heuristics (see DateNode for details).

gavo.svcs.vizierexprs.parseFloat(s, pos, tok)

gavo.svcs.vizierexprs.parseNumericExpr(str, baseSymbol={expr StringEnd})

returns a parse tree for vizier-like expressions over floats.

gavo.svcs.vizierexprs.parseStringExpr(str, baseSymbol={StringExpr StringEnd})