1d6e260533
* cleanup magefile; antlr stuff * fixed broken magefile * Tidy up grammar directory * antlr tools |
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|---|---|---|
| .. | ||
| testdata | ||
| antlr-4.11.1-complete.jar | ||
| generate.go | ||
| generate.sh | ||
| README.md | ||
| SLQ.g4 | ||
SLQ Grammar
The query language used by sq is formally known as SLQ. The
grammar is defined in SLQ.g4, which is an ANTLR4 grammar.
There's a bunch of valid sample input in the testdata dir.
The antlr4 tool generates the parser / lexer files from the grammar.
Being that antlr4 is Java-based, Java must be installed to regenerate
from the grammar. The process is encapsulated in generate.sh (or execute
go generate ./...).
The generated .go files ultimately end up in package libsq/ast/internal/slq. Files
in this directory should not be directly edited.
The libsq/ast.Parse function takes a SLQ input string and returns an *ast.AST.
The entrypoint that accepts the SLQ string is libsq.ExecuteSLQ, which ultimately
invokes ast.Parse.
Working with the grammar
You probably should install the antlr tools.
pip install antlr4-tools
You may also find antlr4ts useful.
npm install antlr4ts
And there are various IDE plugins available.
In particular, note the VS Code extension.