Alphabetical syntax and API lookup
Search for the word or symbol you see in a program. A row identifies its role at that occurrence: language syntax, contextual grammar, a compiler-provided name, or an ordinary library API. A compositional form such as is not nothing is not one indivisible keyword. This lookup does not make every word in a clause globally reserved; the vocabulary appendix and each construct's grammar define legal contexts. Use @ to escape an identifier where required.
Capitalization does not select a different source symbol. In the API table, conventional .NET casing identifies the familiar type/method spelling, not a second keyword. A type import, an assembly reference and an optional feature declaration have separate roles.
Words and forms
| Search | Role | Use | Exact rules |
|---|---|---|---|
#define |
Language form | Define a typed compile-time name with = and a value | 25 |
#define override |
Language form | Deliberately replace an existing replaceable definition; not an implicit last-definition rule | 25 |
#elif |
Language form | Continue a compile-time conditional with another condition | 25 |
#else |
Language form | Select the remaining compile-time branch | 25 |
#endif |
Language form | Close a preprocessor conditional | 25 |
#if |
Language form | Select preprocessed source from a compile-time Boolean condition | 25 |
#ifdef |
Language form | Test whether a compile-time name is defined | 25 |
#ifndef |
Language form | Test whether a compile-time name is not defined | 25 |
#include |
Language form | Insert a permitted source fragment while preserving source locations and diagnosing cycles | 25 |
#undef |
Language form | Remove a definition under its source/configuration scope rules | 25 |
__compiler__ |
Compiler context | Deterministic compile-time metadata and naming inputs | 26 |
_case_sensitive |
Language form | Suffix on supported text/pattern predicates; not a standalone statement | 16 |
abstract |
Language form | Require a concrete implementation under the class/member declaration rules | 9 |
action |
Language form | Declare a callable operation, optionally with a logical result | 8 |
add_handler |
Language form | Subscribe a compatible handler to an event | 19 |
alias |
Language form | Bind a visible symbol to a compile-time spelling; aliasing a property does not cache its value | 3 |
all |
Language form | Join every required producer; also appears in distinct service grammar | 17 |
and |
Language form | Evaluate the right Boolean operand only when the left is true | 6 |
another |
Language form | Register an additional service rather than accidentally colliding with an existing identity | 20 |
any |
Language form | Select the first completed producer, including failure, then join; selection alone does not cancel losers | 17 |
arguments |
Compiler context | Select a current parameter statically; not a runtime dictionary | 3 |
as |
Language form | State a type or applicable binding under the enclosing declaration/expression grammar | 5 |
ascii |
Language form | Test the supported text against ASCII constraints | 16 |
assembly |
Language form | Apply attributes to the assembly through project declarations | 21 |
async |
Declaration modifier | Fix the asynchronous contract; explicit async actions supply their standard cancellation context | 17 |
atomic |
Coordination form | Short protected synchronous operation; no suspension, implicit deep copy or transaction | 17 |
attributes |
Language form | Attach CLR attributes at their permitted declaration targets | 21 |
auto_import_directsharp |
Language form | Enable or disable only the automatic DirectSharp root import | 3 |
await |
Language form | Explicitly observe one awaitable result/failure; does not recursively flatten nested tasks | 17 |
block |
Language form | Introduce an explicit lexical block without changing enclosing action return semantics | 14 |
break |
Control flow | Leave the innermost loop, or a named enclosing loop with break identifier; concurrent work already admitted is joined without automatic cancellation | 7 |
call |
Language form | Invoke a callable value under the declared delegate contract | 8 |
calls |
Language form | Bind a feature operation to an ordinary library/adapter member | 23 |
Cancellation |
Compiler context | Recognized cancellation-aware action or owned producer context; inference alone does not grant it | 17 |
captured |
Language form | Mark a feature operand for typed captured-expression binding | 23 |
case |
Language form | Define a select branch; cases do not fall through | 7 |
catch |
Language form | Handle a matching protected failure using its actual exception type | 13 |
checked |
Language form | Select checked arithmetic/conversion behavior in its permitted context | 6 |
class |
Language form | Declare an ordinary reference type with its stated member/access contracts | 9 |
class kind |
Declaration form | Reuse a class header; exposes optionally selects its type-use contract, without a runtime base class | 9 |
clear_flag |
Language form | Clear the selected flag bits without inventing unrelated values | 11 |
collect |
Language form | Supply an iteration-local result for a declared concurrent collection | 17 |
collects |
Language form | Declare a concurrent result collection whose publication preserves source order | 17 |
concurrent |
Language form | Own overlapping branches or loop bodies under a structured lifetime | 17 |
const |
Language form | Declare a value subject to compile-time constant restrictions | 5.7 |
constants |
Language form | Group type-level constants under shared visibility | 5.7 |
constructor |
Language form | Declare construction explicitly; not an ordinary action or an on-create hook | 9 |
consume |
Acquisition loop | Acquire forward-only work until completion; temporary emptiness can mean wait | 15 |
containing |
Language form | Test text containment under the selected comparison policy | 16 |
context |
Language form | Name a feature subject when an implicit dot receiver would be ambiguous | 23 |
continue |
Control flow | Finish the innermost iteration, or the named enclosing iteration with continue identifier; does not return from the containing action | 7 |
conversions |
Language form | Declare supported conversion protocols rather than ad hoc parsing syntax | 4 |
convert |
Language form | Request the applicable conversion contract; failures propagate | 4 |
copy_of |
Copy expression | Make a shallow copy using the supported concrete-type contract; referenced children remain shared | 9 |
creates |
Language form | Declare the effect that creates a feature current value | 23 |
current |
Feature context | Current adapted value within declared feature operations | 23 |
CurrentLoop |
Compiler context | Current loop observation metadata in its supported context | 7 |
data |
Language form | Declare a record-like value with its required construction and stored-state equality rules | 9 |
decimal |
Language form | Recognize a supported decimal text shape after is; distinct from the Decimal type name | 16 |
declares |
Language form | Introduce a typed runtime-bound symbol through a feature operation | 23 |
default |
Value/declaration form | Resolve a typed effective default, or declare one; no universal new-object rule | 4 |
default for |
Default declaration | Supply an external default subject to visibility, locking and ambiguity rules | 4 |
default_wrapper_engine |
Project setting | Select the default wrapper engine under compile-time configuration | 24 |
description |
Language form | Attach structured documentation metadata | 21 |
dispose |
Authored cleanup | Declare a synchronous cleanup route; async dispose declares the asynchronous route explicitly | 14 |
div |
Language form | Divide first, then convert the whole-number quotient toward zero under the numeric rules | 6 |
else |
Language form | Choose the unmatched conditional/select branch | 7 |
elseif |
Language form | Continue conditional selection with a further condition | 7 |
end |
Language form | Close a block; use the construct qualifier, such as end action | 14 |
ending_with |
Language form | Test a text suffix under the selected comparison policy | 16 |
engine |
Language form | Select the wrapper engine within wrapper application grammar | 24 |
ensure |
Contract | Check successful action exit against its logical result and captured entry values | 12 |
enter |
Language form | Acquire a Gate permit before its protected body; failed acquisition enters no body | 17 |
enum |
Type declaration | Declare named enum values with their ordinary CLR-compatible representation | 11 |
eq_case_sensitive |
Language form | Compare supported values with explicit case-sensitive text semantics | 6 |
event |
Language form | Declare an event under its delegate, accessibility and raising rules | 19 |
exit |
Control flow | Bare form equals break; targeted forms require a matching legal enclosing construct | 7 |
exit for |
Language form | Leave the nearest matching for_each loop where the targeted exit is legal | 7 |
exposes |
Language form | Choose the type-use contract of a class kind without creating a runtime kind type | 9 |
expression |
Language form | Type a captured feature expression under its target delegate/expression contract | 23 |
extension |
Declaration form | Declare an extension with an explicit receiver and its normal binding restrictions | 22 |
false |
Language form | Boolean false value | 5 |
feature |
Language form | Declare an optional typed adapter over existing APIs; not unrestricted code generation | 23 |
field |
Compiler context | Stored-property backing storage where the accessor establishes it | 9 |
fields |
Language form | Select supported field representation in construction/member grammar | 9 |
finally |
Language form | Run cleanup when leaving protected work, including return and exceptional exits | 13 |
first |
Language form | Select the first successful producer; request cooperative loser cancellation and still join | 17 |
flags |
Type declaration | Declare a flag enum with the supported bit tests and updates | 11 |
for |
Contextual target | The target in exit for; numeric iteration uses for_each … in range | 7 |
for_each |
Loop form | Visit a source or a numeric range; async enumeration performs generated waits | 7 |
forever |
Language form | Select the unbounded repeat form, subject to explicit control flow | 7 |
from |
Language form | Bind a source in extraction/acquisition or use the declared yield-from form | 8 |
get |
Accessor grammar | Read a declared property; field is available only where its backing-storage context is established | 9 |
Global |
Compiler namespace root | Start qualification at the actual CLR/global namespace root | 3 |
goto |
Control flow | Jump forward or backward to a mark; preserve scope, initialization, cleanup and concurrency boundaries | 7 |
handles_event |
Language form | Declare an event-handler relationship in the supported member context | 19 |
has constructor |
Generic constraint phrase | Require ordinary public parameterless construction for a declared generic parameter; no DI argument completion | Generic constraints |
has_flag |
Language form | Test flag presence; parenthesized and/or conditions have distinct all/either meanings | 11 |
has_not_flag |
Language form | Negate the complete selected flag condition | 11 |
if |
Language form | Choose a statement branch or evaluate the conditional expression form | 7 |
implements |
Type relationship | Declare interface intent or a generic interface restriction; named blocks scope compatible same-name members | 10 |
implicit |
Language form | Declare only a supported implicit conversion; not a general conversion bypass | 4 |
import |
Language form | Add visible names to lookup; never install a missing package or load an assembly | 3 |
in |
Language form | Bind the visited source in for_each or its numeric range form | 15 |
in_case_sensitive |
String predicate form | Select the supported String-only case-sensitive membership comparison | 16 |
inherits |
Type relationship | Select the accessible compatible base, including an applicable generic base restriction | 10 |
integer |
Language form | Recognize a supported integral text shape after is; distinct from the Integer type | 16 |
interface |
Type declaration | Declare a fixed interface contract; implementations require explicit or scoped named intent | 10 |
internal |
Language form | Restrict declaration visibility to its permitted assembly/compilation scope | 9 |
is |
Contextual grammar | Type relationship or the start of a supported predicate; not interchangeable with value equality | 4 |
is a |
Language form | Test runtime type compatibility | 4 |
is empty |
Language form | Test the applicable empty state, distinct from general actual absence | 16 |
is exactly |
Language form | Test exact runtime type rather than assignable derived types | 4 |
is faulted |
Language form | Inspect cached lazy failure without forcing initialization | 16 |
is in |
Predicate grammar | Test membership; collection comparers retain their own contracts | 16 |
is initialized |
Language form | Inspect successful lazy initialization, including successful nothing, without forcing it | 16 |
is not |
Language form | Negate an applicable is predicate; not a separate equality precedence group | 4 |
is nothing |
Language form | Test actual absence rather than an effective default value | 16 |
is same_as |
Language form | Test reference identity rather than value equality | 4 |
is whitespace |
Language form | Test supported text whitespace under the predicate contract | 16 |
is working |
Language form | Inspect lazy initialization in progress without forcing it | 16 |
iso_date |
Language form | Recognize the selected ISO date text shape, not arbitrary culture-dependent parsing | 16 |
key |
Language form | Supply an exact service identity key under the service contract | 20 |
LastAttempt |
Compiler context | Initialized lexical attempt record; completed try/try_get updates it, including successful absence | 13 |
LastLoop |
Compiler context | Last completed loop observation metadata in its supported context | 7 |
lazy |
Initializer form | Force once on ordinary value use; cache success/absence/failure, with non-forcing state predicates | 18 |
leave |
Language form | End the Gate-protected region and release an acquired permit | 17 |
let |
Declaration form | Initialize a local; let from extracts once from a required present source | 5 |
let_if |
Declaration form | Conditional extraction: missing source assigns nothing to all extracted locals; failures still propagate | 5 |
like |
Language form | Match the supported lightweight pattern syntax | 16 |
limit |
Language form | Bound complete concurrent branches/iterations with a positive integer or shared Gate | 17 |
lock default |
Default declaration | Preserve the type default against external replacement | 4 |
MainServiceProvider |
Recognized service context | Main-provider fallback under the service model; not a wildcard lifetime guarantee | 20 |
mark |
Control flow | Declare a statement destination, without a colon or a new block | 7 |
match |
Language form | Use regex matching with the documented typed capture rules | 16 |
mod |
Language form | Compute the remainder under resolved numeric operand rules | 6 |
namespace |
Language form | Declare a namespace relative to root_namespace unless Global-qualified | 3 |
needs |
Language form | Declare an explicit dependency with constructor/storage and ownership rules | 20 |
new |
Language form | Construct an instance under the selected constructor and initialization contract | 9 |
not |
Language form | Negate a Boolean expression under the declared operator precedence | 6 |
not_eq_case_sensitive |
Language form | Use explicitly case-sensitive inequality | 6 |
nothing |
Value form | Actual absence; distinct from a type-specific effective default | 4 |
numeric |
Language form | Test the supported numeric text shape rather than assume a culture-specific parser | 16 |
of |
Generic type grammar | Supply type parameters or arguments under the applicable generic declaration/call | 4 |
old_value_of |
Contract expression | Capture eligible entry state once, including before body guards; not a later local snapshot | 12 |
one of |
Type form | Declare a selected union of permitted types under its stated constraints | 11 |
operation |
Language form | Declare feature-local vocabulary and explicit effects | 23 |
or |
Language form | Evaluate the right Boolean operand only when the left is false | 6 |
order_by |
Contextual loop grammar | Order loop input; distinct from the ordinary LINQ OrderBy method | 7 |
otherwise |
Language form | Supply a contract message/exception expression; not arbitrary alternative control flow | 12 |
outer |
Language form | Promote the declared local exactly one scope outward; its initializer still runs at the authored statement | 5 |
overridable |
Language form | Permit replacement of an eligible member in a derived type | 9 |
override |
Indexer modifier | Replace an inherited virtual indexer property with a compatible override | 9 |
overrides |
Language form | Implement an inherited overridable contract with a compatible signature | 9 |
parsable_as |
Language form | Test the supported parsability contract for a target type | 16 |
preset |
Factory/value form | Select an explicitly named preset; it does not replace the unnamed effective default | 4 |
private |
Language form | Restrict access to the applicable containing declaration scope | 9 |
project |
Language form | Declare one effective project configuration; its filename alone has no special binding power | 3 |
properties |
Language form | Select the supported property representation for promoted inputs | 9 |
property |
Member declaration | Declare a property; property [parameters] declares an indexer with get/set accessors and end property | 9 |
protected |
Language form | Allow access under the containing/derived-type visibility rules | 9 |
provide |
Language form | Compose an instance through its effective dependency contract | 20 |
public |
Language form | Expose a declaration subject to the accessibility of its full contract | 9 |
raise_event |
Language form | Invoke the declared event under its normal handler contract | 19 |
range |
Contextual loop grammar | Numeric range with to and optional step; not a promise of a standalone Range API | 7 |
readonly |
Language form | Prevent rebinding/writable-reference use, not transitive object mutation | 9 |
remove_handler |
Language form | Unsubscribe the supplied compatible handler from an event | 19 |
repeat |
Loop form | Counted/forever or post-test loop; the closing form follows its header/trailing condition | 7 |
replaceable |
Language form | Permit reassignment of a replaceable need; required-value checks remain and the previous value is not disposed | 20 |
require |
Contract | Fail-fast check at its written position; otherwise selects a message/exception expression | 12 |
result |
Compiler context | Logical action result used by result assignment and successful-exit checks | 8 |
retry |
Language form | Restart the associated try attempt explicitly; application policy must bound repetition | 13 |
return |
Control flow | Exit an action; inside an inline run, complete that branch after its cleanup and owned joins | 8 |
returns |
Language form | Declare a logical action or producer result; fixed CLR signatures still constrain implementation | 8 |
root_namespace |
Language form | Set the project namespace root; assembly name alone does not establish it | 3 |
run |
Owned producer | Invoke or execute a branch inside concurrent all/first/any; not implicit Task.Run | 17 |
scoped |
Language form | Select the service lifetime associated with an owned scope | 20 |
select |
Language form | Choose a statement branch or a scoped expression result | 7 |
self |
Compiler context | Select the current instance or extension receiver | 3 |
services |
Language form | Compose service registrations with explicit identity and lifetime | 20 |
set |
Accessor grammar | Implement a property write using its incoming value; restricted setter access still differs from readonly | 9 |
set_flag |
Language form | Set the selected flag bits | 11 |
sets |
Language form | Declare replacement of a feature current value from an operation result | 23 |
singleton |
Language form | Select the service lifetime shared through the applicable provider | 20 |
skip |
Contextual loop grammar | Loop shaping clause; library Skip/TrySkip have separate contracts | 7 |
starting_with |
Language form | Test a text prefix under the selected comparison policy | 16 |
static |
Language form | Declare a type-level member rather than an instance member | 9 |
step |
Contextual loop grammar | Explicit range increment in a numeric for_each header | 7 |
take |
Contextual result/loop grammar | Produce a scoped value or shape loop input; library Take/TryTake are separate APIs | 14 |
target |
Language form | Declare the source type adapted by a feature | 23 |
task_of |
Operation/producer query | Capture a fresh invocation, or query an owned result/collection producer; neither relaunches work | 17 |
then |
Language form | Separate a condition from its branch | 7 |
throw |
Language form | Raise a failure; contextual ?? throw requires actual absence | 13 |
timeout |
Language form | Set a supported concurrent/acquisition deadline under its separate cause policy | 17 |
times |
Language form | Specify counted repetition under repeat grammar | 7 |
to |
Language form | Separate inclusive numeric range endpoints or appear in a declared conversion form | 7 |
toggle_flag |
Language form | Flip the selected flag bits | 11 |
transient |
Language form | Select a new service instance per applicable resolution | 20 |
true |
Language form | Boolean true value | 5 |
try |
Language form | Protect an attempt in structured or blockless form and update lexical LastAttempt | 13 |
try_get |
Best-effort computation | Normally catchable acquisition failures become nothing; async failure needs await inside the protected work | 13 |
tryconvert |
Language form | Use a real safe conversion protocol, not a blanket catch around convert | 4 |
unchecked |
Language form | Select unchecked behavior only where the numeric contract permits it | 6 |
until |
Language form | Close a post-test repeat and stop scheduling when its condition is true | 7 |
use |
Receiver scope | Evaluate a required receiver once; does not itself acquire disposal ownership | 14 |
use_if |
Receiver scope | Skip the receiver body when its captured receiver is absent; does not catch failures | 14 |
using |
Owned scope | Acquire resources and clean up in reverse order; choose async cleanup from static contracts and context | 14 |
value |
Compiler context | Incoming property setter value where the accessor establishes it | 9 |
virtual |
Indexer modifier | Permit an indexer property to be overridden with runtime dispatch; action syntax remains overridable | 9 |
where |
Contextual grammar | Generic restrictions, loop/discovery filtering or a declared feature operation; ordinary LINQ Where is a library method | Generic constraints, 7 |
while |
Language form | Continue while a condition holds, either as a loop header or post-test repeat closer | 7 |
with |
Language form | Supply the declared initialization/limit/clause grammar; not a universal copy operation | 9 |
with name: |
Loop clause | Name a loop for break identifier and continue identifier; not an ordinary value declaration | 7 |
wrap |
Language form | Apply a declared wrapper engine under its deterministic asset/target rules | 24 |
yield |
Language form | Produce an iterator value; iterator invocation obtains the sequence rather than executing its body | 8 |
yields |
Language form | Declare a synchronous/asynchronous iterator element type | 8 |
Operators and punctuation
| Search | Meaning | Exact rules |
|---|---|---|
| = / <> | Equality/inequality in expressions; = assigns in an assignment-statement context | Operators |
| ?? / ?? throw | Evaluate a fallback or throw only for actual absence; do not force a deferred sequence | Coalescing |
| .Name (read) | Ordinary property/field reads propagate absence; reached getter failures propagate | Read chains |
| [index] / [key] | Required receiver/location access; not an automatic absent result | Indexing |
| + / - / * / / / div / mod | Typed arithmetic; fractional / differs from quotient-first div | Numeric rules |
| and / or / not | Boolean logic; and/or short-circuit | Binding |
| < / <= / > / >= | Ordering according to resolved operand contracts | Binding |
| .Name / name: expression | Receiver-based or named-parameter callable expression under a target signature | Callables |
| {{expression}} | String interpolation; not C# escape/bracing syntax | Literals |
| @identifier | Escape a keyword spelling as an identifier; identity still ignores case | Names |
| ; | Optional statement separator/terminator | Statements |
| // / /// / /* … */ | Line/documentation/nested block comments; apostrophe instead opens a String | Source |
Libraries and recognized API names
| Search | Role | Contract | Details |
|---|---|---|---|
Chars / Unicode |
DirectSharp library names | UTF-16 units and Unicode scalar helpers; neither promises grapheme indexing | Reference |
ConfigureAwait |
.NET method | Opt out of continuation-context capture for that await; not UI dispatch or forced thread switching | Reference |
Gate |
DirectSharp library type | Borrowed coordination permits; no reentrancy/fairness guarantee; join users before disposal | Reference |
IConsumable<T> |
DirectSharp CLR interface | Forward-only acquisition and explicit completion/cancellation contract | Reference |
MainServiceProvider |
Recognized service context | Main-provider fallback under the service model; not a wildcard lifetime guarantee | Reference |
RuleFor / NotEmpty / EmailAddress |
FluentValidation methods | Ordinary imported validator APIs; not language statements | Reference |
ServiceProvider / ServiceScope / ServiceScopeFactory |
DirectSharp library contracts | Service lookup and lifetime ownership; scopes are explicitly owned or borrowed | Reference |
Skip / TrySkip / TakeLast / TryTakeLast |
DirectSharp library methods | Strict counts versus tolerant selection/remainder with documented timing and zero policies | Reference |
String / Integer / Decimal |
Type names | CLR-compatible type binding, with documented effective defaults and arithmetic behavior | Reference |
swap |
Recognized exchange operation | Exchange writable locations; atomic protection is automatic in concurrent bodies, not a general shared-write rule | Reference |
Take / TryTake |
DirectSharp library methods | Strict deferred selection versus tolerant collected selection; counts and inclusive positions have distinct overload contracts | Reference |
Task.Run |
.NET method | Explicit thread-pool scheduling; await or retain its operation using ordinary intent rules | Reference |
For CLR declarations and source member types, use the API catalogue. Feature effects, discovery and wrapper engine selection have a separate declaration reference.
Additional selected API names: Consumables factories, ILiveConsumable producer completion, opt-in SequenceExtensions, static Chars/Unicode exports, and ServiceNotFoundException constructors. None is a new core keyword.
Use the behavior index for surprising results, the guide to learn a construct, and the library plan for the distinction between public contracts and private compiler support. Imported APIs keep their own signatures, comparison and failure behavior.