The parser does not include parenthesis in the AST, so if a LHS
expression would be parenthesized then its start span would start
after the opening parenthesis. Previously, some parent AST nodes would
be created with the start span of its LHS as its own start, so this
resulted in the parent AST node not encompassing the opening parenthesis
in its source span. This commit fixes the issue by capturing the start
index prior to parsing a child AST tree, which is then used as the
start of the source span of the the parent AST node that is parsed.
Fixes#40721
PR Close#40740
When parsing interpolations, if we encounter an empty interpolation
(`{{}}`), the current code uses a "pretend" value of `$implicit` for the
name as if the interplotion were really `{{$implicit}}`. This is
problematic because the spans are then incorrect downstream since they
are based off of the `$implicit` text.
This commit changes the interpretation of empty interpolations so that
the text is simply an empty string.
Fixes https://github.com/angular/vscode-ng-language-service/issues/1077
Fixes https://github.com/angular/vscode-ng-language-service/issues/1078
PR Close#40583
The Language Service uses the source span of AST nodes to recognize which
node a user has selected, given their cursor position in a template. This is
used to trigger autocompletion.
The previous source span of BindingPipe nodes created a problem when:
1) the pipe binding had no identifier (incomplete or in-progress expression)
2) the user typed trailing whitespace after the pipe character ('|')
For example, the expression `{{foo | }}`. If the cursor preceded the '}' in
that expression, the Language Service was unable to detect that the user was
autocompleting the BindingPipe expression, since the span of the BindingPipe
ended after the '|'.
This commit changes the expression parser to expand the span of BindingPipe
expressions with a missing identifier, to include any trailing whitespace.
This allows the Language Service to correctly recognize this case as
targeting the BindingPipe and complete it successfully. The `nameSpan` of
the BindingPipe is also moved to be right-aligned with the end of any
whitespace present in the pipe binding expression.
This change allows for the disabled test in the Language Service for pipe
completion in this case to be re-enabled.
PR Close#40346
Currently we check whether a property binding contains an interpolation using a regex so
that we can throw an error. The problem is that the regex doesn't account for quotes
which means that something like `[prop]="'{{ foo }}'"` will be considered an error, even
though it's not actually an interpolation.
These changes build on top of the logic from #39826 to account for interpolation
characters inside quotes.
Fixes#39601.
PR Close#40267
Currently the compiler treats something like `{{ '{{a}}' }}` as a nested
binding and throws an error, because it doesn't account for quotes
when it looks for binding characters. These changes add a bit of
logic to skip over text inside quotes when parsing.
Fixes#39601.
PR Close#39826
When parsing for i18n messages, interpolated strings are
split into `Text` and `Placeholder` pieces. The method that
does this `_visitTextWithInterpolation()` was becoming too
complex. This commit refactors that method along with some
associated functions that it uses.
PR Close#39717
Though we currently have the knowledge of where the `key` for an
event binding appears during parsing, we do not propagate this
information to the output AST. This means that once we produce the
template AST, we have no way of mapping a template position to the key
span alone. The best we can currently do is map back to the
`sourceSpan`. This presents problems downstream, specifically for the
language service, where we cannot provide correct information about a
position in a template because the AST is not granular enough.
This is essentially identical to the change from #38898, but for event
bindings rather than input bindings.
PR Close#39609
Currently expressions `$event.foo()` and `this.$event.foo()`, as well as `$any(foo)` and
`this.$any(foo)`, are treated as the same expression by the compiler, because `this` is considered
the same implicit receiver as when the receiver is omitted. This introduces the following issues:
1. Any time something called `$any` is used, it'll be stripped away, leaving only the first parameter.
2. If something called `$event` is used anywhere in a template, it'll be preserved as `$event`,
rather than being rewritten to `ctx.$event`, causing the value to undefined at runtime. This
applies to listener, property and text bindings.
These changes resolve the first issue and part of the second one by preserving anything that
is accessed through `this`, even if it's one of the "special" ones like `$any` or `$event`.
Furthermore, these changes only expose the `$event` global variable inside event listeners,
whereas previously it was available everywhere.
Fixes#30278.
PR Close#39323
This commit handles the following cases:
- incomplete pipes in a pipe chain
- incomplete arguments in a pipe chain
- incomplete arguments provided to a pipe
- nested pipes
The idea is to unconditionally recover on the presence of a pipe, which
should be okay because expression parsing can be independently between
pipes.
PR Close#39437
There is no actionable change in this commit other than to pretty-print
EOF tokens. Actual parsing of unterminated pipes is already supported,
this just adds a test for it.
Part of #38596
PR Close#39113
Prior to this change, expressions within ICUs would have a source span
corresponding with the whole ICU. This commit narrows down the source
spans of these expressions to the exact location in the source file, as
a prerequisite for reporting type check errors within these expressions.
PR Close#39072
This patch refactors the interpolation parser to do so iteratively
rather than using a regex. Doing so prepares us for supporting granular
recovery on poorly-formed interpolations, for example when an
interpolation does not terminate (`{{ 1 + 2`) or is not terminated
properly (`{{ 1 + 2 {{ 2 + 3 }}`).
Part of #38596
PR Close#38977
This patch adds support for recovering well-formed (and near-complete)
ASTs for semantically malformed keyed reads and keyed writes. See the
added tests for details on the types of semantics we can now recover;
in particular, notice that some assumptions are made about the form of
a keyed read/write intended by a user. For example, in the malformed
expression `a[1 + = 2`, we assume that the user meant to write a binary
expression for the key of `a`, and assign that key the value `2`. In
particular, we now parse this as `a[1 + <empty expression>] = 2`. There
are some different interpretations that can be made here, but I think
this is reasonable.
The actual changes in the parser code are fairly minimal (a nice
surprise!); the biggest addition is a `writeContext` that marks whether
the `=` operator can serve as a recovery point after error detection.
Part of #38596
PR Close#39004
Though we currently have the knowledge of where the `key` for an
attribute binding appears during parsing, we do not propagate this
information to the output AST. This means that once we produce the
template AST, we have no way of mapping a template position to the key
span alone. The best we can currently do is map back to the
`sourceSpan`. This presents problems downstream, specifically for the
language service, where we cannot provide correct information about a
position in a template because the AST is not granular enough.
PR Close#38898
The expression parser will split the expression up at the interpolation markers
into expressions and static strings. This commit also captures the positions of
these strings in the expression to be used in source-mapping later.
PR Close#38645
Prior to this change, the unary + and - operators would be parsed as `x - 0`
and `0 - x` respectively. The runtime semantics of these expressions are
equivalent, however they may introduce inaccurate template type checking
errors as the literal type is lost, for example:
```ts
@Component({
template: `<button [disabled]="isAdjacent(-1)"></button>`
})
export class Example {
isAdjacent(direction: -1 | 1): boolean { return false; }
}
```
would incorrectly report a type-check error:
> error TS2345: Argument of type 'number' is not assignable to parameter
of type '-1 | 1'.
Additionally, the translated expression for the unary + operator would be
considered as arithmetic expression with an incompatible left-hand side:
> error TS2362: The left-hand side of an arithmetic operation must be of
type 'any', 'number', 'bigint' or an enum type.
To resolve this issues, the implicit transformation should be avoided.
This commit adds a new unary AST node to represent these expressions,
allowing for more accurate type-checking.
Fixes#20845Fixes#36178
PR Close#37918
Builds on top of #34655 to support more cases that could be using a pipe inside host bindings (e.g. ternary expressions or function calls).
Fixes#37610.
PR Close#37883
ASTs for property read and method calls contain information about
the entire span of the expression, including its receiver. Use cases
like a language service and compile error messages may be more
interested in the span of the direct identifier for which the
expression is constructed (i.e. an accessed property). To support this,
this commit adds a `nameSpan` property on
- `PropertyRead`s
- `SafePropertyRead`s
- `PropertyWrite`s
- `MethodCall`s
- `SafeMethodCall`s
The `nameSpan` property already existed for `BindingPipe`s.
This commit also updates usages of these expressions' `sourceSpan`s in
Ngtsc and the langauge service to use `nameSpan`s where appropriate.
PR Close#36826
This commit propagates the `sourceSpan` and `valueSpan` of a `VariableBinding`
in a microsyntax expression to `ParsedVariable`, and subsequently to
View Engine Variable AST and Ivy Variable AST.
Note that this commit does not propagate the `keySpan`, because it involves
significant changes to the template AST.
PR Close#36047
This commit adds fine-grained text spans to TemplateBinding for microsyntax expressions.
1. Source span
By convention, source span refers to the entire span of the binding,
including its key and value.
2. Key span
Span of the binding key, without any whitespace or keywords like `let`
The value span is captured by the value expression AST.
This is part of a series of PRs to fix source span mapping in microsyntax expression.
For more info, see the doc https://docs.google.com/document/d/1mEVF2pSSMSnOloqOPQTYNiAJO0XQxA1H0BZyESASOrE/edit?usp=sharing
PR Close#35897
TemplateAst values are currently typed as the base class AST, but they
are actually constructed with ASTWithSource. Type them as such, because
ASTWithSource gives more information about the consumed expression AST
to downstream customers (namely, the expression AST source).
Unblocks #35271
PR Close#35892
This commit removes the `NullAstVisitor` and `visitAstChildren` exported
from `packages/compiler/src/expression_parser/ast.ts` because they
contain duplicate and buggy implementation, and their use cases could be
sufficiently covered by `RecursiveAstVisitor` if the latter implements the
`visit` method. This use case is only needed in the language service.
With this change, any visitor that extends `RecursiveAstVisitor` could
just define their own `visit` function and the parent class will behave
correctly.
A bit of historical context:
In language service, we need a way to tranverse the expression AST in a
selective manner based on where the user's cursor is. This means we need a
"filtering" function to decide which node to visit and which node to not
visit. Instead of refactoring `RecursiveAstVisitor` to support this,
`visitAstChildren` was created. `visitAstChildren` duplicates the
implementation of `RecursiveAstVisitor`, but introduced some bugs along
the way. For example, in `visitKeyedWrite`, it visits
```
obj -> key -> obj
```
instead of
```
obj -> key -> value
```
Moreover, because of the following line
```
visitor.visit && visitor.visit(ast, context) || ast.visit(visitor, context);
```
`visitAstChildren` visits every node *twice*.
PR Close#35619
Pipes in host binding expressions are not supported in View Engine and Ivy, but in some more complex cases (like `(value | pipe) === true`) compiler was not reporting errors. This commit extends Ivy logic to detect pipes in host binding expressions and throw in cases bindings are present. View Engine behavior remains the same.
PR Close#34655
In the past, only the starting index of an expression Token has been
recorded, so a parser could demarkate the span of a token only by the
start locations of two tokens. This may lead to trailing whitespace
being included in the token span:
```html
{{ token1 + token2 }}
^^^^^^^^^ recorded span of `token1`
```
It's also not enough for a parser to determine the end of a token by
adding the length of the token value to the token's start location,
because lexed expression values may not exactly reflect the source code.
For example, `"d\\"e"` is lexed as a string token whose value is `d"e`.
Instead, this commit adds a `end` field to expression tokens. `end`
is one past the last index of the token source code. This will enable a
parser to determine the span of a token just by looking at that token.
This is a breaking change because the contructor interface of `Token`
has changed.
Part of #33477.
PR Close#33549
Previously, the type checker would compute an absolute source span by
combining an expression AST node's `ParseSpan` (relative to the start of
the expression) together with the absolute offset of the expression as
represented in a `ParseSourceSpan`, to arrive at a span relative to the
start of the file. This information is now directly available on an
expression AST node in the `AST.sourceSpan` property, which can be used
instead.
PR Close#34417
Expressions in an inline template binding are improperly recorded as
spaning an offset calculated from the start of the template binding
attribute key, whereas they should be calculated from the start of the
attribute value, which contains the actual binding AST.
PR Close#31813
The template parser has a certain interpolation config associated with
it and builds a regular expression each time it needs to extract the
interpolations from an input string. Since the interpolation config is
typically the default of `{{` and `}}`, the regular expression doesn't
have to be recreated each time. Therefore, this commit creates only a
single regular expression instance that is used for the default
configuration.
In a large compilation unit with big templates, computing the regular
expression took circa 275ms. This change reduces this to effectively
zero.
PR Close#34332
Previously the compiler would crash if a pipe was encountered which did not
match any pipe in the scope of a template.
This commit introduces a new diagnostic error for unknown pipes instead.
PR Close#33454
Currently, the spans of expressions are recorded only relative to the
template node that they reside in, not their source file.
Introduce a `sourceSpan` property on expression ASTs that records the
location of an expression relative to the entire source code file that
it is in. This may allow for reducing duplication of effort in
ngtsc/typecheck/src/diagnostics later on as well.
Child of #31898
PR Close#31897
Template AST nodes for (bound) attributes, variables and references will
now retain a reference to the source span of their value, which allows
for more accurate type check diagnostics.
PR Close#30181
Currently, template expressions and statements have their location
recorded relative to the HTML element they are in, with no handle to
absolute location in a source file except for a line/column location.
However, the line/column location is also not entirely accurate, as it
points an entire semantic expression, and not necessarily the start of
an expression recorded by the expression parser.
To support record of the source code expressions originate from, add a
new `sourceSpan` field to `ASTWithSource` that records the absolute byte
offset of an expression within a source code.
Implement part 2 of [refactoring template parsing for
stability](https://hackmd.io/@X3ECPVy-RCuVfba-pnvIpw/BkDUxaW84/%2FMA1oxh6jRXqSmZBcLfYdyw?type=book).
PR Close#31391
Currently the `RecursiveAstVisitor` that is part of the template expression
parser does not _always_ properly pass through the context that can be
specified when visting a given expression. Only a handful of AST types
pass through the context while others are accidentally left out. This causes
unexpected and inconsistent behavior and basically makes the `context`
parameter not usable if the type of template expression is not known.
e.g. the template variable assignment migration currently depends on
the `RecursiveAstVisitor` but sometimes breaks if developers use
things like conditionals in their template variable assignments.
Fixes#31043
PR Close#31085
Testing of Ivy revealed two bugs in the AstMemoryEfficientTransformer
class, a part of existing View Engine compiler infrastructure that's
reused in Ivy. These bugs cause AST expressions not to be transformed
under certain circumstances.
The fix is simple, and tests are added to ensure the specific expression
forms that trigger the issue compile properly under Ivy.
PR Close#28523
When template bindings are being parsed the event handlers
were receiving a source span that included the whole attribute.
Now they get a span that is focussed on the handler itself.
PR Close#28055
Previously, it wasn't possible to compile template that contains pipe in context of ternary operator `{{ 1 ? 2 : 0 | myPipe }}` due to the error `Error: Illegal state: Pipes should have been converted into functions. Pipe: async`.
This PR fixes a typo in expression parser so that pipes are correctly converted into functions.
PR Close#28635
