Qrvey Formula Language
Usage
Transpile function
import { ENGINES, Transpile } from "@qrvey/formula-lang";
const program = "MID(MID(\"This is a test\", 1, 5), 1, 2)"
const transpiled = Transpile(program, ENGINES.ELASTICSEARCH)
console.log(transpiled)the output will be
'This is a test'.substring(1, 5).substring(1, 2)
TranspileAST function
import { ENGINES, TranspileAST } from "@qrvey/formula-lang";
const ast = {
"type": "Program",
"exp": "1 + 2",
"lang": "QrveyLang",
"version": "0.0.0",
"body": {
"operator": "+",
"type": "BinaryExpression",
"left": {
"type": "Literal",
"dataType": "number",
"value": 1
},
"right": {
"type": "Literal",
"dataType": "number",
"value": 2
}
}
}
const transpiled = TranspileAST(ast, ENGINES.ELASTICSEARCH)
console.log(transpiled)the output will be
(1 + 2)
codemirror editor
import { EditorState } from "@codemirror/state";
import { basicSetup } from "codemirror";
import { FormulaHighlight, calculateAST } from "@qrvey/formula-lang"
// set the editor state with the QFormula plugin. This adds the support for
this._state = EditorState.create({
doc: 'Test formula',
extensions: [
basicSetup,
FormulaHighlight(),
...
]
})
// On every edit update you can calculate the AST
private dispatchTextUpdate(state: EditorState) {
const tree = (state as any).tree;
const text = ((state.doc as any).text as Array<string>).join('\n');
const ast = calculateAST(text, tree.topNode);
// dispatch event after return
return { text, ast }
}How create a context
The context is a object where implementor can build the information required for the transpiler. For example, the columns that will be used in the formula.
The properties needed are:
-
useSampleData: (Boolean) If you want to overwrite columns/externalFormulas by custom data, enable this flag. Default:
false -
sampleData: Optional (Object) Object to overwrite columns for custom data. Key represent the ID of the column, Value represent the replacement. See:
__tests__/__mocks__/context.ts>testContext -
timezone: Optional (Object).
{ offset: 'String' }Set the timezone offset in String format. - currentFormulaId: Optional (String): ID of the current formula if you are edited one. This flag help to avoid any Circular Dependency when edit one formula, to avoid call itself
-
model: Optional (Object)
- label: (String): Visualization
- id: (String): ID of item (Column)
- replacement: Optional (String): The ID will be replaced by this value.
- type: (AST_PRIMITIVES) Native type
- isExternalFormula: Optional (Boolean): If the item is a Formula created by this Package, need to set this flag in true
Use this Interfaces and Constants to build a Context
import { FormulaContext, AST_PRIMITIVES } from '"@qrvey/formula-lang"';How create clean the context
In some scenarios will be necessary to clean the Context, for example: Delete columns that will cause Circular Dependencies. This package have a utility call: cleanInvalidItemsInContext for that
import { cleanInvalidItemsInContext } from "@qrvey/formula-lang";
const cleanContext = cleanInvalidItemsInContext(dirtyContext);