README
¶
NAME
sheet -- demo of a spreadsheet engine
DESCRIPTION
Sheet demonstrates a minimal engine to support spreadsheets, a table of cells with formulas:
s.Set("A1", "1")
s.Set("B1", "=SUM(A1:A5, 7-6)")
s.Set("B3", "=IF(B1 > 3, 10, 20)")
s.Calculate()
s.VisitAll(func(id, val string, res float64) bool {
fmt.Printf("%s %3.1f\t%s\n", id, res, val)
return true
})
The expected output is:
A1 1.0 1
B1 2.0 =SUM(A1:A5, 7-6)
B3 20.0 =IF(B1 > 3, 10, 20)
Engines
It supports two engines to drive cell parsing and fromula calculation:
-
AST: parse formulas into Abstrast Syntax Tree (AST). Walk the three in postorder traversal.
-
VM: parse formulas into AST, then compile it into instructions. Use a Virtual Machine (VM) to execute the instruction to get the value.
Directories
¶
| Path | Synopsis |
|---|---|
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cmd
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sheet
command
Sheet demonstrates an Excel-like engine to drive a table of cells.
|
Sheet demonstrates an Excel-like engine to drive a table of cells. |
|
wasm
command
Wasm runs spreadsheets in browser using WebAssembler.
|
Wasm runs spreadsheets in browser using WebAssembler. |
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internal
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ast
Package ast defines Abstract Syntax Tree (AST) nodes for a sheet cell.
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Package ast defines Abstract Syntax Tree (AST) nodes for a sheet cell. |
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lex
Package lex implements formula lexical analysis of cells.
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Package lex implements formula lexical analysis of cells. |
|
sheet
Package sheet implements a cells table.
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Package sheet implements a cells table. |
|
vm
Package vm implements a virtual machine (VM) to generate an instructions set from parsed cell's Abstract Syntax Tree (AST) for Intermediate Representation (IR) and execute these to calculate the cell value.
|
Package vm implements a virtual machine (VM) to generate an instructions set from parsed cell's Abstract Syntax Tree (AST) for Intermediate Representation (IR) and execute these to calculate the cell value. |
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