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Computed expressions respect left-to-right associativity and operator precedence #1090

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merged 13 commits into from
Jun 24, 2020
Merged

Computed expressions respect left-to-right associativity and operator precedence #1090

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241259d
WIP: associative operators without parens
sc1f Jun 9, 2020
f203cd7
Associative operators
sc1f Jun 9, 2020
353938a
WIP: actually actually associative operators
sc1f Jun 10, 2020
8be7542
add exponent precedence
sc1f Jun 10, 2020
0c29b3e
reformat parser tests
sc1f Jun 10, 2020
220413c
functions can now have arbitary expressions inside of them without pa…
sc1f Jun 10, 2020
507ddeb
Add invariant tests for expression parser
sc1f Jun 11, 2020
b4a8232
Add more invariant tests
sc1f Jun 11, 2020
0371d4b
WIP: autocomplete fixes for associative expressions, select the right…
sc1f Jun 12, 2020
94a77a4
Reduce usage of get_last_token functions and replace with actual bool…
sc1f Jun 15, 2020
58a2d61
Errors and tokens render side to side in expression editor, thus text…
sc1f Jun 15, 2020
3dfcbef
Only render operators/functions of the correct types
sc1f Jun 15, 2020
d6011b9
reduce the amount of times tokens are cleaned of whitespace
sc1f Jun 16, 2020
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WIP: associative operators without parens
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@sc1f
sc1f committed Jun 23, 2020
commit 241259df5225e399678c6e0243634ac267d390ae
168 changes: 141 additions & 27 deletions packages/perspective-viewer/src/js/computed_expressions/computed_expression_parser.js
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Original file line number Diff line number Diff line change
Expand Up @@ -120,6 +120,8 @@ class PerspectiveComputedExpressionParser {
throw new Error(message);
}

console.log(cst);

return this._visitor.visit(cst);
}

Expand Down Expand Up @@ -343,13 +345,7 @@ class PerspectiveComputedExpressionParser {
}

Expression(ctx, computed_columns) {
if (ctx.OperatorComputedColumn) {
this.visit(ctx.OperatorComputedColumn, computed_columns);
} else if (ctx.FunctionComputedColumn) {
this.visit(ctx.FunctionComputedColumn, computed_columns);
} else {
return;
}
return this.visit(ctx.OperatorComputedColumn, computed_columns);
}

/**
Expand All @@ -359,38 +355,151 @@ class PerspectiveComputedExpressionParser {
* @param {*} ctx
*/
OperatorComputedColumn(ctx, computed_columns) {
console.log("operator", ctx);
// TODO: collapse body
let left = this.visit(ctx.left, computed_columns);

if (typeof left === "undefined") {
left = computed_columns[computed_columns.length - 1].column;
}
let final_column_name;

let operator = this.visit(ctx.Operator);
if (ctx.right) {
let previous;

if (!operator) {
return;
ctx.right.forEach((rhs, idx) => {
let operator = this.visit(ctx.Operator[idx]);

if (!operator) {
return;
}

let right = this.visit(rhs, computed_columns);

// If there is a previous value, use it, otherwise use
// the leftmost value. This enables expressions such as
// a + b / c * d + e ... ad infinitum
const left_hand = previous ? previous : left;

console.log(left_hand, operator, right);

// Use custom name if provided through `AS/as/As`
const as = this.visit(ctx.as);
const column_name = as ? as : COMPUTED_FUNCTION_FORMATTERS[operator](left_hand, right);

computed_columns.push({
column: column_name,
computed_function_name: operator,
inputs: [left_hand, right]
});

previous = column_name;
});

final_column_name = previous;
} else {
// If there are no more right-hand tokens, return the
// column name so it can be used as the tree traversal
// goes upwards.
final_column_name = left;
}

let right = this.visit(ctx.right, computed_columns);
return final_column_name;
}

AdditionOperatorComputedColumn(ctx, computed_columns) {
console.log("addition", ctx);
let left = this.visit(ctx.left, computed_columns);

let final_column_name;

if (ctx.right) {
let previous;

ctx.right.forEach((rhs, idx) => {
let operator = this.visit(ctx.Operator[idx]);

if (!operator) {
return;
}

let right = this.visit(rhs, computed_columns);

// If there is a previous value, use it, otherwise use
// the leftmost value. This enables expressions such as
// a + b / c * d + e ... ad infinitum
const left_hand = previous ? previous : left;

if (typeof right === "undefined") {
right = computed_columns[computed_columns.length - 1].column;
console.log(left_hand, operator, right);

// Use custom name if provided through `AS/as/As`
const as = this.visit(ctx.as);
const column_name = as ? as : COMPUTED_FUNCTION_FORMATTERS[operator](left_hand, right);

computed_columns.push({
column: column_name,
computed_function_name: operator,
inputs: [left_hand, right]
});

previous = column_name;
});

final_column_name = previous;
} else {
// If there are no more right-hand tokens, return the
// column name so it can be used as the tree traversal
// goes upwards.
final_column_name = left;
}

let as = this.visit(ctx.as);
return final_column_name;
}

MultiplicationOperatorComputedColumn(ctx, computed_columns) {
console.log("multiply", ctx);
let left = this.visit(ctx.left, computed_columns);

let column_name = COMPUTED_FUNCTION_FORMATTERS[operator](left, right);
let final_column_name;

// Use custom name if provided through `AS/as/As`
if (as) {
column_name = as;
if (ctx.right) {
let previous;

ctx.right.forEach((rhs, idx) => {
let operator = this.visit(ctx.Operator[idx]);

if (!operator) {
return;
}

let right = this.visit(rhs, computed_columns);

// If there is a previous value, use it, otherwise use
// the leftmost value. This enables expressions such as
// a + b / c * d + e ... ad infinitum
const left_hand = previous ? previous : left;

console.log(left_hand, operator, right);

// Use custom name if provided through `AS/as/As`
const as = this.visit(ctx.as);
const column_name = as ? as : COMPUTED_FUNCTION_FORMATTERS[operator](left_hand, right);

computed_columns.push({
column: column_name,
computed_function_name: operator,
inputs: [left_hand, right]
});

previous = column_name;
});

final_column_name = previous;
} else {
// If there are no more right-hand tokens, return the
// column name so it can be used as the tree traversal
// goes upwards.
final_column_name = left;
}

computed_columns.push({
column: column_name,
computed_function_name: operator,
inputs: [left, right]
});
return final_column_name;
}

/**
Expand Down Expand Up @@ -419,11 +528,13 @@ class PerspectiveComputedExpressionParser {

const as = this.visit(ctx.as);

let column_name = COMPUTED_FUNCTION_FORMATTERS[fn](...input_columns);
let column_name;

// Use custom name if provided through `AS/as/As`
if (as) {
column_name = as;
} else {
column_name = COMPUTED_FUNCTION_FORMATTERS[fn](...input_columns);
}

const computed = {
Expand All @@ -433,6 +544,9 @@ class PerspectiveComputedExpressionParser {
};

computed_columns.push(computed);

// Return the column name so it can be used up the chain
return column_name;
}

/**
Expand Down
47 changes: 27 additions & 20 deletions packages/perspective-viewer/src/js/computed_expressions/parser.js
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Original file line number Diff line number Diff line change
Expand Up @@ -20,28 +20,24 @@ export class ComputedExpressionColumnParser extends CstParser {
});

this.RULE("Expression", () => {
this.OR(
[
{
ALT: () => {
this.SUBRULE(this.OperatorComputedColumn);
}
},
{
ALT: () => {
this.SUBRULE(this.FunctionComputedColumn);
}
}
],
{
ERR_MSG: "Expected an expression of the form `x + y` or `func(x)`."
}
);
// Preserve operator precedence amongst mathematical operations
this.SUBRULE(this.AdditionOperatorComputedColumn);
});

this.RULE("AdditionOperatorComputedColumn", () => {
this.SUBRULE(this.ColumnName, {LABEL: "left"});
this.MANY(() => {
this.SUBRULE(this.Operator);
this.SUBRULE2(this.MultiplicationOperatorComputedColumn, {LABEL: "right"});
});
this.OPTION(() => {
this.SUBRULE(this.As, {LABEL: "as"});
});
});

this.RULE("OperatorComputedColumn", () => {
this.RULE("MultiplicationOperatorComputedColumn", () => {
this.SUBRULE(this.ColumnName, {LABEL: "left"});
this.AT_LEAST_ONE(() => {
this.MANY(() => {
this.SUBRULE(this.Operator);
this.SUBRULE2(this.ColumnName, {LABEL: "right"});
});
Expand All @@ -50,6 +46,17 @@ export class ComputedExpressionColumnParser extends CstParser {
});
});

// this.RULE("OperatorComputedColumn", () => {
// this.SUBRULE(this.ColumnName, {LABEL: "left"});
// this.AT_LEAST_ONE(() => {
// this.SUBRULE(this.Operator);
// this.SUBRULE2(this.ColumnName, {LABEL: "right"});
// });
// this.OPTION(() => {
// this.SUBRULE(this.As, {LABEL: "as"});
// });
// });

this.RULE("FunctionComputedColumn", () => {
this.SUBRULE(this.Function);
this.CONSUME(vocabulary["leftParen"]);
Expand All @@ -66,7 +73,7 @@ export class ComputedExpressionColumnParser extends CstParser {
});

this.RULE("ColumnName", () => {
this.OR([{ALT: () => this.SUBRULE(this.ParentheticalExpression)}, {ALT: () => this.CONSUME(vocabulary["columnName"])}], {
this.OR([{ALT: () => this.SUBRULE(this.ParentheticalExpression)}, {ALT: () => this.SUBRULE(this.FunctionComputedColumn)}, {ALT: () => this.CONSUME(vocabulary["columnName"])}], {
ERR_MSG: "Expected a column name (wrapped in double quotes) or a parenthesis-wrapped expression."
});
});
Expand Down
2 changes: 2 additions & 0 deletions packages/perspective-viewer/src/js/computed_expressions/widget.js
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Original file line number Diff line number Diff line change
Expand Up @@ -298,6 +298,8 @@ class ComputedExpressionWidget extends HTMLElement {
return;
}

console.log("Parsed:", this._parsed_expression);

// Take the parsed expression and type check it on the viewer,
// which will call `_type_check_expression()` with a computed_schema.
const event = new CustomEvent("perspective-computed-expression-type-check", {
Expand Down
24 changes: 23 additions & 1 deletion packages/perspective-viewer/test/js/unit/computed_expressions_parser.spec.js
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Original file line number Diff line number Diff line change
Expand Up @@ -41,7 +41,7 @@ describe("Computed Expression Parser", function() {
expect(parsed).toEqual(expected);
});

it.skip("Should parse an operator notation expression with associativity", function() {
it("Should parse an operator notation expression with associativity", function() {
const expected = [
{
column: "(w + x)",
Expand All @@ -58,6 +58,28 @@ describe("Computed Expression Parser", function() {
expect(parsed).toEqual(expected);
});

it("Should parse an operator notation expression with associativity and operator precedence", function() {
const expected = [
{
column: "(w * x)",
computed_function_name: "*",
inputs: ["w", "x"]
},
{
column: "(z / abc)",
computed_function_name: "/",
inputs: ["w", "abc"]
},
{
column: "((w * x) + (z / abc))",
computed_function_name: "+",
inputs: ["(w + x)", "(z / abc)"]
}
];
const parsed = COMPUTED_EXPRESSION_PARSER.parse('"w" * "x" + "z" / "abc"');
expect(parsed).toEqual(expected);
});

it("Should parse an operator notation expression named with 'AS'", function() {
const expected = [
{
Expand Down