Snobol4 语言 实战 输入输出格式控制与美化

Snobol4^【1】 语言实战：输入输出格式控制与美化

Snobol4 是一种古老的编程语言，最初于1962年由David J. Farber、Ralph E. Griswold 和 Ivan P. Polonsky 在美国贝尔实验室开发。尽管它的历史可以追溯到计算机科学的早期，但Snobol4 仍然以其独特的语法和强大的文本处理能力而闻名。本文将围绕Snobol4 语言，探讨如何进行输入输出格式控制与美化。

Snobol4 简介

Snobol4 是一种高级编程语言，特别适合于文本处理任务。它具有以下特点：

- 模式匹配^【3】：Snobol4 支持强大的模式匹配功能，可以轻松处理字符串。
- 动态数据结构^【4】：Snobol4 支持动态数据结构，如列表和表。
- 流控制^【5】：Snobol4 提供了丰富的流控制结构，如循环和条件语句。

输入输出格式控制

在Snobol4 中，输入输出格式控制主要通过以下几种方式实现：

1. 输入控制^【6】

Snobol4 提供了多种输入函数，如 `read` 和 `in`，用于从标准输入读取数据。

snobol
read line


这段代码将从标准输入读取一行文本，并将其存储在变量 `line<sup>【7】</sup>` 中。

2. 输出控制^【8】

输出控制主要通过 `print<sup>【9】</sup>` 函数实现，可以控制输出的格式。

snobol
print line


这段代码将变量 `line` 的值输出到标准输出。

3. 格式化输出^【10】

snobol^【2】4 支持格式化输出，可以使用 `printf` 函数。

snobol
printf "%s has %d characters", line, length(line)


这段代码将输出 `line` 的值和它的长度。

输出美化^【11】

输出美化是提高程序可读性的重要手段。以下是一些在Snobol4 中实现输出美化的方法：

1. 使用换行符^【12】

在输出文本时，使用换行符 `^` 可以使文本更加清晰。

snobol
print "This is a new line"^
"This is another line"


2. 使用制表符^【13】

制表符 `^t` 可以用于对齐文本。

snobol
print "Name"^t "Age"^t "Country"
print "Alice"^t "30"^t "USA"
print "Bob"^t "25"^t "Canada"


3. 使用颜色

虽然Snobol4 本身不支持颜色输出^【14】，但可以通过输出特殊字符来模拟颜色效果。

snobol
print "^[31mThis is red text^[0m"


这段代码将输出红色文本。

实战案例

以下是一个使用Snobol4 实现的简单文本美化程序，它将读取用户输入的文本，然后以美化后的格式输出。

```snobol
input line
print "Original text: "^
line
print "formatted text<sup>【15】</sup>:"^
"^tWord<sup>【16】</sup>"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"^t"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