Model Context

Examples

Refer to the Using model_context class section for code examples on how to use the model_context class.

API Reference

class model_context

This class stores all data relevant to current session. You can think of this like a document model for each formula calculation run. Note that only those methods called from the formula interpreter are specified in the interface; this explains why accessors for the most part only have the ‘get’ method not paired with its ‘set’ counterpart.

Public Functions

model_context()
model_context(const rc_size_t &sheet_size)
~model_context()
formula_result_wait_policy_t get_formula_result_wait_policy() const

Query the current policy on what to do when a formula cell result is being requested while the result has not yet been computed.

void notify(formula_event_t event)

This method is used to notify the model access implementer of formula events.

Parameters:

event – event type.

const config &get_config() const
dirty_cell_tracker &get_cell_tracker()
const dirty_cell_tracker &get_cell_tracker() const
bool is_empty(const abs_address_t &addr) const
bool is_empty(const abs_range_t &range) const
celltype_t get_celltype(const abs_address_t &addr) const
cell_value_t get_cell_value_type(const abs_address_t &addr) const
double get_numeric_value(const abs_address_t &addr) const

Get a numeric representation of the cell value at specified position. If the cell at the specified position is a formula cell and its result has not yet been computed, it will block until the result becomes available.

Parameters:

addr – position of the cell.

Returns:

numeric representation of the cell value.

bool get_boolean_value(const abs_address_t &addr) const
string_id_t get_string_identifier(const abs_address_t &addr) const
std::string_view get_string_value(const abs_address_t &addr) const

Get a string value associated with the cell at the specified position. It returns a valid string value only when the cell is a string cell, or is a formula cell containing a string result. Otherwise, it returns a nullptr.

Parameters:

addr – position of the cell.

Returns:

pointer to a string value if the cell stores a valid string value, else nullptr.

const formula_cell *get_formula_cell(const abs_address_t &addr) const
formula_cell *get_formula_cell(const abs_address_t &addr)
formula_result get_formula_result(const abs_address_t &addr) const
const named_expression_t *get_named_expression(sheet_t sheet, std::string_view name) const

Get a named expression token set associated with specified name if present. It first searches the local sheet scope for the name, then if it’s not present, it searches the global scope.

Parameters:
  • sheet – index of the sheet scope to search in.

  • name – name of the expression.

Returns:

const pointer to the token set if exists, nullptr otherwise.

double count_range(const abs_range_t &range, values_t values_type) const
matrix get_range_value(const abs_range_t &range) const

Obtain range value in matrix form. Multi-sheet ranges are not supported. If the specified range consists of multiple sheets, it throws an exception.

Parameters:

range – absolute, single-sheet range address. Multi-sheet ranges are not allowed.

Returns:

range value represented as matrix.

std::unique_ptr<iface::session_handler> create_session_handler()

Session handler instance receives various events from the formula interpretation run, in order to respond to those events. This is optional; the model context implementation is not required to provide a handler.

Returns:

a new session handler instance. It may be nullptr.

iface::table_handler *get_table_handler()

Table interface provides access to all table ranges stored in the document model. A table is a 2-dimensional range of cells that include named columns. It is used when resolving a table reference that refers to a cell or a range of cells by the table name and/or column name.

Returns:

non-null pointer to the table storage inside the model, or nullptr if no table is present or supported by the model implementation.

const iface::table_handler *get_table_handler() const
string_id_t add_string(std::string_view s)

Try to add a new string to the string pool. If the same string already exists in the pool, the new string won’t be added to the pool.

Parameters:

s – string to try to add to the pool.

Returns:

string_id_t integer value representing the string.

const std::string *get_string(string_id_t identifier) const
sheet_t get_sheet_index(std::string_view name) const

Get the index of sheet from sheet name. If the sheet name doesn’t exist, it returns a value equal to ixion::invalid_sheet.

Parameters:

name – sheet name.

Returns:

0-based sheet index, or ixion::invalid_sheet in case the document doesn’t have a sheet by the specified name.

std::string get_sheet_name(sheet_t sheet) const
rc_size_t get_sheet_size() const

Get the size of a sheet.

Returns:

sheet size.

size_t get_sheet_count() const

Return the number of sheets.

Returns:

number of sheets.

string_id_t append_string(std::string_view s)
void set_sheet_size(const rc_size_t &sheet_size)
void set_config(const config &cfg)
void empty_cell(const abs_address_t &addr)
void set_numeric_cell(const abs_address_t &addr, double val)
void set_boolean_cell(const abs_address_t &adr, bool val)
void set_string_cell(const abs_address_t &addr, std::string_view s)
void set_string_cell(const abs_address_t &addr, string_id_t identifier)
cell_access get_cell_access(const abs_address_t &addr) const
void fill_down_cells(const abs_address_t &src, size_t n_dst)

Duplicate the value of the source cell to one or more cells located immediately below it.

Parameters:
  • src – position of the source cell to copy the value from.

  • n_dst – number of cells below to copy the value to. It must be at least one.

formula_cell *set_formula_cell(const abs_address_t &addr, formula_tokens_t tokens)

Set a formula cell at a specified address.

Parameters:
  • addr – address at which to set a formula cell.

  • tokens – formula tokens to put into the formula cell.

Returns:

pointer to the formula cell instance inserted into the model.

formula_cell *set_formula_cell(const abs_address_t &addr, const formula_tokens_store_ptr_t &tokens)

Set a formula cell at a specified address. This variant takes a formula tokens store that can be shared between multiple formula cell instances.

Parameters:
  • addr – address at which to set a formula cell.

  • tokens – formula tokens to put into the formula cell.

Returns:

pointer to the formula cell instance inserted into the model.

formula_cell *set_formula_cell(const abs_address_t &addr, const formula_tokens_store_ptr_t &tokens, formula_result result)

Set a formula cell at a specified address. This variant takes a formula tokens store that can be shared between multiple formula cell instances.

Parameters:
  • addr – address at which to set a formula cell.

  • tokens – formula tokens to put into the formula cell.

  • result – cached result of this formula cell.

Returns:

pointer to the formula cell instance inserted into the model.

void set_grouped_formula_cells(const abs_range_t &group_range, formula_tokens_t tokens)
void set_grouped_formula_cells(const abs_range_t &group_range, formula_tokens_t tokens, formula_result result)
abs_range_t get_data_range(sheet_t sheet) const
void set_named_expression(std::string name, formula_tokens_t expr)

Set a named expression associated with a string name in the global scope.

Parameters:
  • name – name of the expression.

  • expr – formula tokens to use for the named expression.

void set_named_expression(std::string name, const abs_address_t &origin, formula_tokens_t expr)

Set a named expression associated with a string name in the global scope.

Parameters:
  • name – name of the expression.

  • origin – position of the origin cell. Origin cell is relevant only when you need to convert the tokens into a string representation.

  • expr – formula tokens to use for the named expression.

void set_named_expression(sheet_t sheet, std::string name, formula_tokens_t expr)

Set a named expression associated with a string name in a sheet-local scope.

Parameters:
  • sheet – 0-based index of the sheet to register this expression with.

  • name – name of the expression.

  • expr – formula tokens to use for the named expression.

void set_named_expression(sheet_t sheet, std::string name, const abs_address_t &origin, formula_tokens_t expr)

Set a named expression associated with a string name in a sheet-local scope.

Parameters:
  • sheet – 0-based index of the sheet to register this expression with.

  • name – name of the expression.

  • origin – position of the origin cell. Origin cell is relevant only when you need to convert the tokens into a string representation.

  • expr – formula tokens to use for the named expression.

sheet_t append_sheet(std::string name)

Append a new sheet to the model. The caller must ensure that the name of the new sheet is unique within the model context. When the name being used for the new sheet already exists, it throws a model_context_error exception.

Parameters:

name – name of the sheet to be inserted.

Throws:

model_context_error

Returns:

sheet index of the inserted sheet.

void set_cell_values(sheet_t sheet, std::initializer_list<input_row> rows)

A convenient way to mass-insert a range of cell values. You can use a nested initializet list representing a range of cell values. The outer list represents rows.

Parameters:
  • sheet – sheet index.

  • rows – nested list of cell values. The outer list represents rows.

void set_session_handler_factory(session_handler_factory *factory)
void set_table_handler(iface::table_handler *handler)
size_t get_string_count() const
void dump_strings() const
string_id_t get_identifier_from_string(std::string_view s) const

Get an integer string ID from a string value. If the string value doesn’t exist in the pool, the value equal to empty_string_id gets returned.

Parameters:

s – string value.

Returns:

string_id_t integer string ID associated with the string value given.

model_iterator get_model_iterator(sheet_t sheet, rc_direction_t dir, const abs_rc_range_t &range) const

Get an immutable iterator that lets you iterate cell values in one sheet one at a time. The caller has to ensure that the model content does not change for the duration of the iteration.

Parameters:
  • sheet – sheet index.

  • dir – direction of the iteration.

  • range – range on the specified sheet to iterate over.

Returns:

model iterator instance.

named_expressions_iterator get_named_expressions_iterator() const

Get an iterator for global named expressions.

named_expressions_iterator get_named_expressions_iterator(sheet_t sheet) const

Get an interator for sheet-local named expressions.

Parameters:

sheet – 0-based index of the sheet where the named expressions are stored.

void walk(sheet_t sheet, const abs_rc_range_t &range, column_block_callback_t cb) const
bool empty() const
struct input_cell

Cell value only to be used to input a collection of cells to sheet. Formula cells are not supported.

Public Types

using value_type = std::variant<bool, double, std::string_view>

Public Functions

input_cell(std::nullptr_t)

Initializes the cell to be empty.

input_cell(bool b)

Boolean cell value.

input_cell(const char *s)

The char array must be null-terminated.

input_cell(double v)

Numeric cell value.

input_cell(const input_cell &other)

Public Members

celltype_t type
value_type value
class input_row

Public Functions

input_row(std::initializer_list<input_cell> cells)
const std::initializer_list<input_cell> &cells() const
class session_handler_factory

Public Functions

virtual std::unique_ptr<iface::session_handler> create()
virtual ~session_handler_factory()
struct config

This structure store parameters that influence various aspects of the ixion formula engine.

Public Functions

config()
config(const config &r)

Public Members

char sep_function_arg

Function argument separator. By default it’s ‘,’.

char sep_matrix_column

Matrix column separator.

char sep_matrix_row

Matrix row separator.

int8_t output_precision

Precision to use when converting a numeric value to a string representation. A negative value indicates an unspecified precision.

class model_iterator

Public Functions

model_iterator()
model_iterator(const model_iterator&) = delete
model_iterator(model_iterator &&other)
~model_iterator()
model_iterator &operator=(const model_iterator&) = delete
model_iterator &operator=(model_iterator &&other)
bool has() const
void next()
const cell &get() const

Friends

friend class detail::model_context_impl
struct cell

Public Types

using value_type = std::variant<bool, double, string_id_t, const formula_cell*>

Public Functions

cell()
cell(row_t _row, col_t _col)
cell(row_t _row, col_t _col, bool _b)
cell(row_t _row, col_t _col, string_id_t _s)
cell(row_t _row, col_t _col, double _v)
cell(row_t _row, col_t _col, const formula_cell *_f)
bool operator==(const cell &other) const
bool operator!=(const cell &other) const

Public Members

row_t row
col_t col
celltype_t type
value_type value