Parse utilities

Topics
	Scalar filter processors
	These are internal utilities used by ParseEngine to parse the scalars; normally there is no reason for a user to be manually using these classes.
	Parse in place with existing parser
	parse a mutable YAML source buffer (re)using an existing parser.
	Parse in place with temporary parser
	parse a mutable YAML source buffer.
	Parse in arena with existing parser
	parse a read-only (immutable) YAML source buffer.
	Parse in arena with temporary parser
	parse a read-only (immutable) YAML source buffer.
	Event Handlers
	rapidyaml implements its parsing logic with a two-level model, where a ParseEngine object reads through the YAML source, and dispatches events to an EventHandler bound to the ParseEngine.

Classes
class	c4::yml::ParseEngine< EventHandler >
	This is the main driver of parsing logic: it scans the YAML or JSON source for tokens, and emits the appropriate sequence of parsing events to its event handler. More...

Typedefs
using	c4::yml::Parser = ParseEngine<EventHandlerTree>
	This is the main ryml parser, where the parser events are handled to create a ryml tree.

Functions
id_type	c4::yml::estimate_tree_capacity (csubstr src)
	Quickly inspect the source to estimate the number of nodes the resulting tree is likely to have.

Detailed Description

See also

sample::sample_parse_in_place

sample::sample_parse_in_arena

sample::sample_parse_file

sample::sample_parse_reuse_tree

sample::sample_parse_reuse_parser

sample::sample_parse_reuse_tree_and_parser

sample::sample_location_tracking

Typedef Documentation

Parser

typedef ParseEngine< EventHandlerTree > c4::yml::Parser = ParseEngine<EventHandlerTree>

This is the main ryml parser, where the parser events are handled to create a ryml tree.

Warning

This class cannot parse YAML where there are container keys. This is not a limitation of the ParseEngine, but of the EventHandlerTree, which is present because the Tree does not accept containers as keys. However, the ParseEngine can parse container keys; consult its documentation for more details.

See also

ParserOptions

ParseEngine

EventHandlerTree

Definition at line 19 of file fwd.hpp.

Function Documentation

estimate_tree_capacity()

id_type c4::yml::estimate_tree_capacity

(

csubstr

src

)

Quickly inspect the source to estimate the number of nodes the resulting tree is likely to have.

If a tree is empty before parsing, considerable time will be spent growing it, so calling this to reserve the tree size prior to parsing is likely to result in a time gain. We encourage using this method before parsing, but as always measure its impact in performance to obtain a good trade-off.

Note

since this method is meant for optimizing performance, it is approximate. The result may be actually smaller than the resulting number of nodes, notably if the YAML uses implicit maps as flow seq members as in [these: are, individual: maps].

Definition at line 135 of file parse.cpp.

{
    id_type num_nodes = 1; // root
    for(size_t i = 0; i < src.len; ++i)
    {
        const char c = src.str[i];
        num_nodes += (c == '\n') || (c == ',') || (c == '[') || (c == '{');
    }
    return num_nodes;
}