Internal API¶

Assorted Utilities¶

class htsql.core.util.maybe(value_type)¶

Checks if a value is either None or an instance of the specified type.

Use with isinstance() as in:

isinstance(X, maybe(T))

class htsql.core.util.oneof(*value_types)¶

Checks if a value is an instance of one of the specified types.

Use with isinstance() as in:

isinstance(X, oneof(T1, T2, ...))

class htsql.core.util.listof(item_type)¶

Checks if a value is a list containing elements of the specified type.

Use with isinstance() as in:

isinstance(X, listof(T))

class htsql.core.util.setof(item_type)¶

Checks if a value is a set containing elements of the specified type.

Use with isinstance() as in:

isinstance(X, setof(T))

class htsql.core.util.tupleof(*item_types)¶

Checks if a value is a tuple with the fixed number of elements of the specified types.

Use with isinstance() as in:

isinstance(X, tupleof(T1, T2, ..., TN))

class htsql.core.util.dictof(key_type, item_type)¶

Checks if a value is a dictionary with keys and elements of the specified types.

Use with isinstance() as in:

isinstance(X, dictof(T1, T2))

class htsql.core.util.omapof(item_type)¶

Checks if a value is an omap object with elements of the specified type.

Use with isinstance() as in:

isinstance(X, omapof(T))

class htsql.core.util.subclassof(class_type)¶

Checks if a value is a subclass of the specified class.

Use with isinstance() as in:

isinstance(X, subclassof(T))

class htsql.core.util.filelike¶

Checks if a value is a file or a file-like object.

Usage:

isinstance(X, filelike())

htsql.core.util.aresubclasses(subclasses, superclasses)¶

Takes two lists; checks if each element of the first list is a subclass of the corresponding element in the second list.

subclasses: sequence of type: A list of potential subclasses.
superclasses: sequence of type: A list of potential superclasses.
Returns: bool: True if the check succeeds; False otherwise.

htsql.core.util.isfinite(value)¶: Verifies that the given value is a finite number.

htsql.core.util.trim_doc(doc)¶

Strips indentation from a docstring; also removes leading and trailing blank lines.

doc: str or None: A docstring.

htsql.core.util.to_name(text)¶

Converts a string to a valid HTSQL identifier.

The given text value is transformed as follows:

translated to Unicode normal form C;
converted to lowercase;
has non-alphanumeric characters replaced with underscores;
preceded with an underscore if it starts with a digit;
an empty string is replaced with '_'.

htsql.core.util.urlquote(text, reserved=';/?:@&=+$, ')¶: Replaces non-printable and reserved characters with %XX sequences.

htsql.core.util.to_literal(text)¶

Converts the text value to a valid string literal.

This function escapes all non-printable characters and wraps the text value in single quotes.

htsql.core.util.similar(model, sample)¶

Checks if model is similar to sample.

model: unicode: A model string.
sample: unicode: A sample string.
Returns: bool: True if model is not too much different from sample; False otherwise.

Use for error reporting to suggest alternatives for an unknown model identifier.

class htsql.core.util.TextBuffer(text)¶

Reads the input text in blocks matching some regular expressions.

text: str or unicode: The input text.

reset()¶: Rewinds to the beginning of the text.

peek(pattern)¶

Checks if the head of the buffer matches the given pattern.

pattern: str or unicode: A regular expression pattern.
Returns: bool: True if the buffer head matches the given pattern; False otherwise.

pull(pattern)¶

Reads a text block matching the given pattern from the head of the buffer.

pattern: str or unicode: A regular expression pattern.
Returns: str or unicode or None: A text block; None if the buffer head does not match the pattern.

pull() skips whitespace characters and comments at the head of the buffer.

fail(message)¶

Generates an exception with a fragment of the buffer at the current position included in the error message.

message: str: The error message.

Returns: RuntimeError instance

htsql.core.util.toposort(elements, order, is_total=False)¶

Sorts elements with respect to the given partial order.

Takes a list of elements and a partial order relation. Returns the elements reordered to satisfy the given order.

elements: A list of elements.
order: A function which represents the partial order relation. order(x) takes an element x and produces a list of elements that must preceed x.
is_total: bool: If set, validates that the given partial order is, in fact, total.

This function raises RuntimeError if order is not a valid partial order (contains loops) or when is_total is set and order is not a valid total order.

class htsql.core.util.cachedproperty(getter)¶

Implements a cached property decorator.

The decorator calls the getter function on the first access to the property and saves the result. Any subsequent access to the property returns the saved value.

Usage:

class C(object):
    @cachedproperty
    def field(self):
        # Called once to calculate the field value.
        # [...]
        return value

class htsql.core.util.frozenomap(iterable=None)¶

An ordered immutable mapping.

This container behaves like an immutable dict object with one exception: iterating over the container produces values (rather than keys) in the order they were added to the container.

class htsql.core.util.omap(iterable=None)¶

An ordered mutable mapping.

This container behaves like a dict object with one exception: iterating over the container produces values (rather than keys) in the order they were added to the container.

Overriding an entry does not change its position; delete and insert the entry to move it to the end.

class htsql.core.util.Clonable¶

A clonable object.

Subclasses of Clonable can use clone() and clone_to() methods to create a clone of the given object with a specified set of attributes replaced.

Subclasses of Clonable must follow the following conventions:

Clonable objects must be immutable.
Each subclass must reimplement the __init__ constructor. All arguments of __init__ must be stored as instance attributes unchanged (or, if changed, must still be in the form acceptable by the constructor).
The constructor must not expect a *-wildcard argument.
The constructor may take a **-wildcard argument. In this case, the argument itself and all its entries must be stored as instance attributes.

clone(**replacements)¶

Clones the object assigning new values to selected attributes.

replacements: New attribute values.
Returns: A new object of the same type that has the same attribute values except those for which new values are specified.

clone_to(clone_type, **replacements)¶

Clones the object changing its type and assigning new values to selected attributes.

clone_type: type: The type of the new object.
replacements: New attribute values.
Returns: A new object of the specified type which has the same attribute values as the original object except those for which new values are provided.

class htsql.core.util.Hashable¶

An immutable object with by-value comparison semantics.

A subclass of Hashable should reimplement __basis__() to produce a tuple of all object attributes which uniquely identify the object.

Two Hashable instances are considered equal if they are of the same type and their basis vectors are equal.

class htsql.core.util.Printable¶

An object with default string representation.

A subclass of Printable is expected to reimplement the __unicode__() method.

class htsql.core.util.YAMLable¶

An object with YAML representation.

Subclasses of YAMLable must override __yaml__() to generate a list of (field, value) pairs.

to_yaml()¶: Returns YAML representation of the object.

htsql.core.util.to_yaml(data)¶: Represents the value in YAML format.

class htsql.core.util.DB(engine, database, username=None, password=None, host=None, port=None, options=None)¶

Parameters of a database connection.

engine: str: The type of the database server; e.g., 'pgsql' or 'sqlite'.
database: str: The name of the database; the path to the database file for SQLite.
username: str or None: The user name used for authentication; None to use the default.
password: str or None: The password used for authentication; None to authenticate without providing a password.
host: str or None: The host address; None to use the default or when not applicable.
port: int or None: The port number; None to use the default or when not applicable.
options: dict or None: A dictionary containing extra connection parameters; currently unused.

classmethod parse(value)¶

Parses a connection URI and returns a corresponding DB instance.

value: str, unicode, dict or DB

Returns: DB

A connection URI is a string of the form:

engine://username:password@host:port/database?options

The engine and database fragments are mandatory; the others could be omitted.

If a fragment contains separator characters which cannot be represented literally (such as :, /, @ or ?), the characters should be escaped using %-encoding.

If the connection URI is not in a valid format, ValueError is raised.

parse() also accepts:

a dictionary with keys 'engine', 'database', 'username', 'password', 'host', 'port', 'options';
an instance of DB.

htsql.core.util.autoimport(name)¶

Imports all modules (including subpackages) in a package.

name: str: The package name.

Error Types¶

exception htsql.core.error.HTTPError¶

An exception as an HTTP response.

An instance of HTTPError serves as a simple WSGI application generating an appropriate HTTP error code and displaying the error message.

status = None¶: HTTP status line.

exception htsql.core.error.BadRequestError¶: Represents 400 Bad Request.

exception htsql.core.error.ForbiddenError¶: Represents 403 Forbidden.

exception htsql.core.error.NotFoundError¶: Represents 404 Not Found.

exception htsql.core.error.ConflictError¶: Represents 409 Conflict.

exception htsql.core.error.InternalServerError¶: Represents 500 Internal Server Error.

exception htsql.core.error.NotImplementedError¶: Represents 501 Not Implemented.

exception htsql.core.error.EngineError(message, quote=None)¶: An error generated by the database driver.

exception htsql.core.error.PermissionError(message, quote=None)¶: An error caused by lack of read or write permissions.

class htsql.core.error.Mark(text, start, end)¶

A fragment of an HTSQL query.

text: unicode: The input query string.
start: int: The starting position of the fragment.
end: int: The ending position of the fragment.

A Mark object represents a fragment of an HTSQL query to be used as an error context for error reporting.

classmethod union(*nodes)¶

Generates a new Mark object as a cover for a fragment collection.

nodes: A list of Mark instances or objects with a mark attribute; None entries are ignored.

excerpt()¶: Returns a list of lines that forms an excerpt of the original query string with ^ characters underlining the marked fragment.

Syntax Parsing¶

The htsql.core.syn package defines the grammar of HTSQL and implements the HTSQL parser. Call parse.parse() to convert a raw query string to a syntax tree. This conversion is performed in three steps:

Decoding: transmission artefacts are removed from the input stream of characters.
Lexical scanning: the input stream of characters is converted to a sequence of lexical tokens.
Syntax parsing: a sequence of lexical tokens is converted to a syntax tree.

Data nodes¶

class htsql.core.syn.token.Token(code, text)¶

A lexical token.

code: unicode: The token type indicator; for operator symbols and punctuation characters, coincides with the token value. By convention, code equal to "" indicates EOF.
text: unicode: The token value.

class htsql.core.syn.syntax.Syntax¶: A syntax node.

class htsql.core.syn.syntax.VoidSyntax¶

Represents a syntax node with no meaning.

Use when a syntax node is required structurally, but no regular nodes are available.

class htsql.core.syn.syntax.SkipSyntax¶

A skip symbol.

class htsql.core.syn.syntax.AssignSyntax(larm, rarm)¶

Assignment expression.

<larm> := <rarm>

larm: SpecifySyntax: The left-hand side of assignment.
rarm: Syntax: The assigned value.

class htsql.core.syn.syntax.SpecifySyntax(larms, rarms)¶

Left-hand side of an assignment expression.

<larm>
<larm> . <larm> ...
<larm> . <larm> ... (<rarm>, ...)

larms: [IdentifierSyntax or ReferenceSyntax]: A chain of identifiers or references separated by . symbol.
rarms: [IdentifierSyntax or ReferenceSyntax] or None: Formal parameters; None if no ().
identifier: IdentifierSyntax: Set only if the specifier is an identifier.
reference: ReferenceSyntax: Set only if the specifier is a reference.

class htsql.core.syn.syntax.ApplySyntax(name, arguments)¶

Function or operator application.

This is an abstract class; concrete subclasses correspond to different syntax forms of functions and operators.

name: unicode: Normalized function name or operator symbol.
arguments: list of Syntax: Function arguments or operands of the operator.

class htsql.core.syn.syntax.FunctionSyntax(identifier, arms)¶

Function call notation.

<identifier> (<arm>, ...)

identifier: IdentifierSyntax: The function name.
arms: list of Syntax: Function arguments.

class htsql.core.syn.syntax.PipeSyntax(identifier, larm, rarms, is_flow, is_open)¶

Pipe notation for function application.

<larm> :<identifier>
<larm> :<identifier> <rarm>
<larm> :<identifier> (<rarm>, ...)
<larm> /:<identifier> (<rarm>, ...)

identifier: IdentifierSyntax: The function name.
larm: Syntax: The first argument.
rarms: [Syntax]: The rest of the arguments.
is_flow: bool: True for flow (:), False for segment (/:) notation.
is_open: bool: True if no right-hand arguments or a single right-hand argument not enclosed in parentheses.

class htsql.core.syn.syntax.OperatorSyntax(symbol, larm, rarm)¶

Binary operator.

<larm> <symbol> <rarm>

symbol: unicode: The operator symbol.
larm: Syntax: The left-hand operand.
rarm: Syntax: The right-hand operand.

class htsql.core.syn.syntax.PrefixSyntax(symbol, arm)¶

Unary operator.

<symbol> <arm>

symbol: unicode: The operator symbol.
arm: Syntax: The operand.

class htsql.core.syn.syntax.FilterSyntax(larm, rarm)¶

Filtering operator.

<larm> ? <rarm>

class htsql.core.syn.syntax.ProjectSyntax(larm, rarm)¶

Projection operator.

<larm> ^ <rarm>

class htsql.core.syn.syntax.LinkSyntax(larm, rarm)¶

Linking operator (deprecated).

<larm> -> <rarm>

class htsql.core.syn.syntax.AttachSyntax(larm, rarm)¶

Attachment operator.

<larm> @ <rarm>

class htsql.core.syn.syntax.DetachSyntax(arm)¶

Detachment operator.

@ <arm>

class htsql.core.syn.syntax.CollectSyntax(arm)¶

Collection operator.

/ <arm>

class htsql.core.syn.syntax.DirectSyntax(symbol, arm)¶

Sorting direction indicator.

<arm> +
<arm> -

symbol: unicode ('+' or '-'): The indicator.
arm: Syntax: The operand.

class htsql.core.syn.syntax.ComposeSyntax(larm, rarm)¶

Composition expression.

<larm> . <rarm>

larm: Syntax: The left-hand operand.
rarm: Syntax: The right-hand operand.

class htsql.core.syn.syntax.UnpackSyntax(index, is_open)¶

Unpacking expression.

*
* <index>
* (<index>)

index: int, long or None: The number of the field to unpack (1-based).
is_open: bool: True if no ().

class htsql.core.syn.syntax.LiftSyntax¶

The lift symbol.

class htsql.core.syn.syntax.GroupSyntax(arm)¶

An expression in parentheses.

(<arm>)

arm: Syntax: The expression.

class htsql.core.syn.syntax.SelectSyntax(larm, rarm)¶

Selection operator.

<larm> {...}

larm: Syntax: The operand.
rarm: RecordSyntax: The selection record.

class htsql.core.syn.syntax.LocateSyntax(larm, rarm)¶

Location operator.

<larm> [...]

larm: Syntax: The operand.
rarm: IdentitySyntax: The identity.

class htsql.core.syn.syntax.RecordSyntax(arms)¶

Record constructor.

{<arm>, ...}

arms: [Syntax]: Record fields.

class htsql.core.syn.syntax.ListSyntax(arms)¶

List constructor.

(<arm>, ...)

arms: [Syntax]: List elements.

class htsql.core.syn.syntax.IdentitySyntax(arms, is_hard)¶

Identity constructor.

[<arm> . ...]
(<arm> . ...)

arms: [Syntax]: Identity labels.
is_hard: bool: True for square brackets ([]), False for parentheses (()).

class htsql.core.syn.syntax.ReferenceSyntax(identifier)¶

Reference expression.

$ <identifier>

identifier: IdentifierSyntax: The reference name.
name: unicode: Normalized identifier name.

class htsql.core.syn.syntax.IdentifierSyntax(text)¶

An identifier.

<text>

text: unicode: The raw identifier name.
name: unicode: Normalized name.

class htsql.core.syn.syntax.LiteralSyntax(text)¶

A literal expression.

This is an abstract class; concrete subclasses for different forms of literal expressions.

text: unicode: The value of the literal.

class htsql.core.syn.syntax.StringSyntax(text)¶

A string literal.

A string literal is a sequence of characters enclosed in single quotes.

class htsql.core.syn.syntax.LabelSyntax(text)¶

A label literal.

A label literal is a sequence of alphanumeric characters or - in an identity constructor.

class htsql.core.syn.syntax.NumberSyntax(text, value)¶

A number literal.

value: int, long, decimal.Decimal, or float.: The numeric value.

class htsql.core.syn.syntax.IntegerSyntax(text)¶: An integer literal.

class htsql.core.syn.syntax.DecimalSyntax(text)¶

A decimal literal.

A decimal literal is a number with a decimal point.

class htsql.core.syn.syntax.FloatSyntax(text)¶

A float literal.

A float literal is a number in exponential notation.

Processes¶

htsql.core.syn.decode.decode(text)¶

Removes transmission artefacts.

text: str or unicode: A raw query string.
Returns: unicode: A processed string; ready for syntax analysis.

%-encoded octets are decoded; the input text is converted to Unicode.

htsql.core.syn.scan.prepare_scan(*args, **kwds)¶: Returns a lexical scanner for HTSQL grammar.

htsql.core.syn.scan.scan(text, start=None)¶

Tokenizes the input query string.

text: str or unicode: A raw query string.
start: unicode or None: The initial lexical rule (by default, the first rule in the grammar).
Returns: [Token]: List of tokens.

htsql.core.syn.parse.prepare_parse(*args, **kwds)¶: Returns a syntax parser for HTSQL grammar.

htsql.core.syn.parse.parse(text, start=None)¶

Parses the input query string into a syntax tree.

text: str or unicode: A raw query string.
start: unicode or None: The initial production rule (by default, the first rule in the grammar).
Returns: Syntax: The corresponding syntax tree.

Scanner and parser generators¶

class htsql.core.syn.grammar.LexicalGrammar¶

Defines a lexical grammar and generates a tokenizer.

add_rule(name)¶: Adds and returns a new tokenizer rule.

add_signal(descriptor)¶

Adds and returns a signal rule.

A signal rule injects a signal token in front of a matched sequence of tokens.

descriptor: str

A string of the form:

<name>: <pattern>

where <name> is the name of a defined signal token, <pattern> is a regular expression for matching a sequence of tokens.

class htsql.core.syn.grammar.LexicalRule(name)¶

Tokenizer context for a lexical grammar.

add_token(descriptor, error=None, is_junk=False, is_symbol=False, unquote=None, pop=None, push=None)¶

Adds a token pattern.

descriptor: str

A string of the form:

<name>: <pattern>

where <name> is the token code, <pattern> is a regular expression for matching input characters.

error: str or None

If set, an error is raised when the token is recognized.

is_junk: bool

If set, the token is not emitted.

is_symbol: bool

If set, <name> is ignored and the token code is equal to the token value.

unquote: unicode -> unicode or None

If set, apply to the token value.

pop: int or None

If set, exit from the pop top tokenizer contexts.

push: unicode or None

If set, enter a new tokenizer context.

class htsql.core.syn.grammar.SyntaxGrammar¶

Defines a syntax grammar and generates a parser.

add_rule(descriptor, match=None, fail=None)¶

Adds and returns a production rule.

descriptor: str

A string of the form:

<name>: <pattern>

where <name> is the production name, <pattern> is a regular expression for matching tokens and other productions.

match: ParseStream -> [Syntax]

A function called when the rule matches a sequence of tokens. The function returns syntax nodes to replace the matched tokens.

fail: (ParseStream, Token) -> exception

A function called when the rule is unable to finish matching a sequence of tokens. The function takes a stream of nodes and a blocking token and returns an exception object.

class htsql.core.syn.grammar.ParseStream(nodes)¶

A buffer of Token and Syntax nodes.

reset()¶: Rewinds to the beginning of the buffer.

pull()¶: Pulls the next node from the buffer.

peek(code)¶: Checks if the next node is a Token object with the given code.

Data Types¶

class htsql.core.domain.Domain¶

An HTSQL data type.

A domain specifies the type of a value. Most HTSQL domains correspond to SQL data types, others represent HTSQL containers (record, list) or used only in special circumstances.

A value of a specific domain could be represented in two forms:

as an HTSQL literal (text);
as a native Python object (data).

Methods parse() and dump() translate values from one form to the other.

static parse(text)¶

Converts an HTSQL literal to a native Python object.

Raises ValueError if the literal is not in a valid format.

text: unicode or None: An HTSQL literal representing a value of the given domain.
Returns: A native Python object representing the same value.

static dump(data)¶

Converts a native Python object to an HTSQL literal.

data: (acceptable types depend on the domain): A native Python object representing a value of the given domain.
Returns: unicode or None: An HTSQL literal representing the same value.

class htsql.core.domain.Value(domain, data)¶

Represents data and its type.

domain: Domain: The data type.
data: The data value.

Instances of Value are iterable and permit len() operator when the data type is ListDomain.

In Boolean context, an instance of Value evaluates to False if and only if data is None.

class htsql.core.domain.Profile(domain, **attributes)¶

Describes the structure of data.

domain: Domain: The data type.
attributes: Extra stuctural metadata. Each entry of attributes becomes an attribute of the Profile instance.

class htsql.core.domain.Product(meta, data, **attributes)¶

Represents data and associated metadata.

meta: Profile: Structure of the data.
data: The data value.
attributes: Extra runtime metadata. Each entry of attributes becomes an attribute of the Product instance.

class htsql.core.domain.NullDomain¶

A domain with no values (except null).

This is an abstract class.

class htsql.core.domain.VoidDomain¶

A domain without any valid values.

This domain is could be used when a domain object is required structurally, but has no semantics.

class htsql.core.domain.EntityDomain¶

The type of class entities.

Since class entities are not observable directly in HTSQL model, this domain does not support any values.

class htsql.core.domain.UntypedDomain¶

Represents a yet undetermined type.

This domain is assigned to HTSQL literals temporarily until the actual domain could be derived from the context.

class htsql.core.domain.BooleanDomain¶

A Boolean data type.

Valid literals: 'true', 'false'.

Valid native objects: bool values.

class htsql.core.domain.NumberDomain¶

A numeric data type.

This is an abstract superclass for integer, float and decimal numbers.

Class attributes:

is_exact: bool: Indicates whether the domain represents exact values.
radix: 2 or 10: Indicates whether the values are stored in binary or decimal form.

class htsql.core.domain.IntegerDomain(size=None)¶

A binary integer data type.

Valid literals: integers (in base 10) with an optional sign.

Valid native objects: int or long values.

size: int or None: Number of bits used to store a value; None if not known.

class htsql.core.domain.FloatDomain(size=None)¶

An IEEE 754 float data type.

Valid literals: floating-point numbers in decimal or exponential format.

Valid native objects: float values.

size: int or None: Number of bits used to store a value; None if not known.

class htsql.core.domain.DecimalDomain(precision=None, scale=None)¶

An exact decimal data type.

Valid literals: floating-point numbers in decimal or exponential format.

Valid native objects: decimal.Decimal objects.

precision: int or None: Number of significant digits; None if infinite or not known.
scale: int or None: Number of significant digits in the fractional part; zero for integers, None if infinite or not known.

class htsql.core.domain.TextDomain(length=None, is_varying=True)¶

A text data type.

Valid literals: any.

Valid native object: unicode values; the NUL character is not allowed.

length: int or None: The maximum length of the value; None if infinite or not known.
is_varying: bool: Indicates whether values are fixed-length or variable-length.

class htsql.core.domain.EnumDomain(labels)¶

An enumeration data type.

An enumeration domain has a predefined finite set of valid text values.

labels: [unicode]: List of valid values.

class htsql.core.domain.DateDomain¶

A date data type.

Valid literals: valid dates in the form YYYY-MM-DD.

Valid native objects: datetime.date values.

class htsql.core.domain.TimeDomain¶

A time data type.

Valid literals: valid time values in the form HH:MM[:SS[.SSSSSS]].

Valid native objects: datetime.time values.

class htsql.core.domain.DateTimeDomain¶

A date+time data type.

Valid literals: valid date+time values in the form YYYY-MM-DD HH:MM[:SS[.SSSSSS]].

Valid native objects: datetime.datetime values.

class htsql.core.domain.OpaqueDomain¶

An unsupported SQL data type.

This domain is used for SQL data types not supported by HTSQL.

Valid literals: any.

Valid native objects: any.

class htsql.core.domain.Record¶

A record value.

Record is implemented as a tuple with named fields.

classmethod make(name, fields, _cache=<WeakValueDictionary at 3056717740>)¶

Generates a Record subclass with the given fields.

name: str, unicode or None.

The name of the new class.

fields: list of str, unicode or None.

List of desired field names (None for a field to have no name).

A field may get no or another name assigned if the desired field name is not available for some reason; e.g., if it is is already taked by another field or if it coincides with a Python keyword.

Returns: subclass of Record

The generated class.

class htsql.core.domain.ContainerDomain¶

A container type.

This is an abstract superclass for container domains.

class htsql.core.domain.ListDomain(item_domain)¶

A variable-size collection of homogenous entries.

Valid literals: quoted entries, comma-separated and wrapped in ( and ).

Valid native objects: list values.

item_domain: Domain: The type of entries.

class htsql.core.domain.RecordDomain(fields)¶

A fixed-size collection of heterogenous entries.

Valid literals: quoted entries, comma-separated and wrapped in { and }.

Valid native objects: tuple values.

fields: [Profile]: The types and other structural metadata of the record fields.

class htsql.core.domain.ID¶

An identity value.

ID is a tuple with a string representation that produces the identity value in literal form.

classmethod make(dump, _cache=<WeakValueDictionary at 3056369900>)¶

Generates a ID subclass with the given string serialization.

dump: Implementation of unicode() operator.
Returns: subclass of ID: The generated class.

class htsql.core.domain.IdentityDomain(labels)¶

A unique identifier of a database entity.

Valid literals: identity constructors as in HTSQL grammar; outer brackets are optional and always stripped.

Valid native objects: tuple values.

labels: [Domain]: The type of labels that form the identity value.
width: int: The number of leaf labels.
leaves: [[int]]: Paths (as tuple indexes) to leaf labels.