free 2d barcode generator asp.net I LANGUAGE-ORIENTED PROGRAMMING in Font

Encoder Data Matrix 2d barcode in Font I LANGUAGE-ORIENTED PROGRAMMING

CHAPTER 11 I LANGUAGE-ORIENTED PROGRAMMING
Encoding ECC200 In None
Using Barcode generation for Font Control to generate, create Data Matrix 2d barcode image in Font applications.
www.OnBarcode.com
Barcode Creation In None
Using Barcode creator for Font Control to generate, create Barcode image in Font applications.
www.OnBarcode.com
Interpreting the AST
Generate Code 128 In None
Using Barcode maker for Font Control to generate, create Code 128 image in Font applications.
www.OnBarcode.com
UCC-128 Creator In None
Using Barcode maker for Font Control to generate, create UCC-128 image in Font applications.
www.OnBarcode.com
When you have created your AST, you have two choices; you can either interpret it or compile it. Interpreting it simply means walking the tree and performing actions as you go. Compiling it means changing it into some other form that is easier, or more typically faster, for the machine to execute. This section will examine interpreting the results, and the next will look at the options for compiling them; finally, you will look at when you should use interpretation and when you should use compilation. The following example shows a short interpreter for your program. The main work of interpreting the AST is done by the function interpret, which walks the tree performing the necessary action as it goes. The logic is quite simple. If you find a literal value or an identifier, you simply return the appropriate value. | Ident (s) -> variableDict.[s] | Val (v) -> v If you find an operand, you recursively evaluate the expressions it contains to obtain their values and then perform the operation: | Multi (e1, e2) -> (interpretInner e1) * (interpretInner e2) Listing 11-3 gives the full interpreter. Listing 11-3. Interpreting an AST Generated from Command-Line Input #light open System.Collections.Generic open Strangelights.ExpressionParser.Ast // requesting a value for variable from the user let getVariableValues e = let rec getVariableValuesInner input (variables : Map<string, float>) = match input with | Ident (s) -> match variables.TryFind(s) with | Some _ -> variables | None -> printf "%s: " s let v = read_float() variables.Add(s,v) | Multi (e1, e2) -> variables |> getVariableValuesInner e1 |> getVariableValuesInner e2 | Div (e1, e2) -> variables |> getVariableValuesInner e1 |> getVariableValuesInner e2
UPC - 13 Creation In None
Using Barcode encoder for Font Control to generate, create EAN / UCC - 13 image in Font applications.
www.OnBarcode.com
UPC-A Supplement 5 Drawer In None
Using Barcode encoder for Font Control to generate, create GS1 - 12 image in Font applications.
www.OnBarcode.com
CHAPTER 11 I LANGUAGE-ORIENTED PROGRAMMING
PDF-417 2d Barcode Generator In None
Using Barcode generator for Font Control to generate, create PDF 417 image in Font applications.
www.OnBarcode.com
Interleaved 2 Of 5 Drawer In None
Using Barcode maker for Font Control to generate, create 2 of 5 Interleaved image in Font applications.
www.OnBarcode.com
| Plus (e1, e2) -> variables |> getVariableValuesInner e1 |> getVariableValuesInner e2 | Minus (e1, e2) -> variables |> getVariableValuesInner e1 |> getVariableValuesInner e2 | _ -> variables getVariableValuesInner e (Map.Empty()) // function to handle the interpretation let interpret input (variableDict : Map<string,float>) = let rec interpretInner input = match input with | Ident (s) -> variableDict.[s] | Val (v) -> v | Multi (e1, e2) -> (interpretInner e1) * (interpretInner e2) | Div (e1, e2) -> (interpretInner e1) / (interpretInner e2) | Plus (e1, e2) -> (interpretInner e1) + (interpretInner e2) | Minus (e1, e2) -> (interpretInner e1) - (interpretInner e2) interpretInner input // request input from user and interpret it printf "input expression: " let lexbuf = Lexing.from_string (read_line()) let e = Pars.Expression Lex.token lexbuf let args = getVariableValues e let v = interpret e args printf "result: %f" v read_line() The results of this example, when compiled and executed, are as follows: input expression: (1 + 3) * [my var] [my var]: 12 result: 48.000000
Making Data Matrix 2d Barcode In None
Using Barcode maker for Software Control to generate, create Data Matrix 2d barcode image in Software applications.
www.OnBarcode.com
Encode Data Matrix 2d Barcode In Java
Using Barcode maker for Android Control to generate, create Data Matrix image in Android applications.
www.OnBarcode.com
Compiling the AST
Generating Code 3/9 In Java
Using Barcode printer for Android Control to generate, create Code 39 Full ASCII image in Android applications.
www.OnBarcode.com
GS1 128 Encoder In Java
Using Barcode creator for Android Control to generate, create UCC - 12 image in Android applications.
www.OnBarcode.com
To many, compilation means generating native code, so it has a reputation for being difficult. But it doesn t have to mean generating native code, and for a DSL you typically generate some other more general-purpose programming language. The .NET Framework provides several features for compiling an AST into a program. Your choice of technology depends on several factors. For example, if you re targeting your language at developers, it might be enough to generate a text file containing F#, some
Make UPC-A Supplement 2 In VS .NET
Using Barcode maker for Reporting Service Control to generate, create Universal Product Code version A image in Reporting Service applications.
www.OnBarcode.com
European Article Number 13 Creator In Java
Using Barcode maker for BIRT reports Control to generate, create EAN13 image in BIRT reports applications.
www.OnBarcode.com
CHAPTER 11 I LANGUAGE-ORIENTED PROGRAMMING
Print Linear In C#.NET
Using Barcode generation for Visual Studio .NET Control to generate, create Linear image in Visual Studio .NET applications.
www.OnBarcode.com
Painting GS1-128 In None
Using Barcode generator for Online Control to generate, create GS1-128 image in Online applications.
www.OnBarcode.com
other language, or a compiled assembly that can then used within an application. However, if you re targeting end users, you will almost certainly have to compile and then execute it on the fly. Table 11-3 summarizes the various options available. Table 11-3. .NET Code-Generation Technologies
Scan Universal Product Code Version A In .NET Framework
Using Barcode scanner for Visual Studio .NET Control to read, scan read, scan image in VS .NET applications.
www.OnBarcode.com
Draw Barcode In Java
Using Barcode generation for Android Control to generate, create Barcode image in Android applications.
www.OnBarcode.com
Technology
Matrix Printer In Java
Using Barcode drawer for Java Control to generate, create 2D image in Java applications.
www.OnBarcode.com
Reading ANSI/AIM Code 128 In Visual C#.NET
Using Barcode recognizer for .NET framework Control to read, scan read, scan image in .NET applications.
www.OnBarcode.com
Microsoft.CSharp. CSharpCodeProvider
Description
This class supports compilation of a C# file that has been created on the fly, either by using simple string concatenation or by using the System.CodeDom namespace. Once the code has been compiled into an assembly, it can be loaded dynamically into memory and executed via reflection. This operation is relatively expensive, because it requires writing to the disk and using reflection to execute methods. This is a set of classes aimed at abstracting between operations available in different languages. The idea is that you describe your operations using the classes available in this namespace and then use a provider to compile them into the language of your choice. .NET ships with a provider for both C# and Visual Basic. Providers for other languages are available for download. They are often the results of community projects. This namespace allows you to build up assemblies using IL. Since IL offers more features than either F#, C#, or System.CodeDom, it provides more flexibility; however, it is lower level so requires more patience and will probably take more time to get right. This is a library written in F# for manipulating IL. It provides roughly the same functionality as System.Reflection.Emit, but F# programmers might find it is more suited to their style of programming than the options available in System.Reflection.Emit.
Copyright © OnBarcode.com . All rights reserved.