commit 44c21e670f35997af7d554da7814925109cc15b8 Author: Ben Ashton Date: Sat Sep 3 00:31:55 2022 -0600 Initial commit diff --git a/cli.js b/cli.js new file mode 100644 index 0000000..721f6c2 --- /dev/null +++ b/cli.js @@ -0,0 +1,24 @@ +import { TemplateEngine } from './index.js'; +import { basename } from 'node:path'; + +// Check arguments +if (process.argv.length !== 3) { + console.error(`Usage: node ${basename(process.argv[1])} filename`); + process.exit(1); +} +const fileName = process.argv[2]; + +const tp = new TemplateEngine(); + +let result; + +try { + result = await tp.render(fileName); +} catch (e) { + console.error(e.message); + process.exit(1); +} + +if (result) { + process.stdout.write(result); +} diff --git a/example_templates/everything.n0m b/example_templates/everything.n0m new file mode 100644 index 0000000..25d5d56 --- /dev/null +++ b/example_templates/everything.n0m @@ -0,0 +1,14 @@ +$ #!/bin/sh +$ title='My Website'; +$ dangerous='Unescaped'; + + + # This is a comment + + <% $title %> + + +

Welcome: <% $2 %>

+ + diff --git a/example_templates/inline_tags.n0m b/example_templates/inline_tags.n0m new file mode 100644 index 0000000..84f6688 --- /dev/null +++ b/example_templates/inline_tags.n0m @@ -0,0 +1,5 @@ +$ VAR1="So many cats!"; +

<% $VAR1 %>

<$% echo $VAR1 | cut -f 2 -d ' ' %>

<$!% echo $VAR1 | cut -f 2 -d ' ' %>

\ No newline at end of file diff --git a/example_templates/restaurants.n0m b/example_templates/restaurants.n0m new file mode 100644 index 0000000..1bd278a --- /dev/null +++ b/example_templates/restaurants.n0m @@ -0,0 +1,12 @@ +$ #!/bin/sh + + + Restaurants + +

<% $restaurant %>

+ + diff --git a/example_templates/restaurants.txt b/example_templates/restaurants.txt new file mode 100644 index 0000000..30bfdb8 --- /dev/null +++ b/example_templates/restaurants.txt @@ -0,0 +1,3 @@ +Luigi's +Papa Johns +SushiQ diff --git a/index.js b/index.js new file mode 100644 index 0000000..d275794 --- /dev/null +++ b/index.js @@ -0,0 +1 @@ +export { TemplateEngine } from './src/template_engine.js'; \ No newline at end of file diff --git a/package.json b/package.json new file mode 100644 index 0000000..a0cab1f --- /dev/null +++ b/package.json @@ -0,0 +1,13 @@ +{ + "name": "n0m-template-engine", + "version": "1.0.0", + "description": "", + "main": "index.js", + "scripts": { + "start": "node cli.js", + "test": "echo \"Error: no test specified\" && exit 1" + }, + "author": "", + "license": "ISC", + "type": "module" +} diff --git a/src/character_stream.js b/src/character_stream.js new file mode 100644 index 0000000..77d94db --- /dev/null +++ b/src/character_stream.js @@ -0,0 +1,85 @@ +import { readFile } from 'node:fs/promises'; +import { basename } from 'node:path'; + +export class CharacterStream { + constructor() { + this.reset(); + } + + reset() { + this._data = ''; + this.fileName = ''; + this._pos = 0; + this.line = 0; + this.column = 0; + } + + async loadFile(fileName) { + this.reset(); + this.fileName = basename(fileName); + this._data = await readFile(fileName, 'utf-8'); + } + + peek(length = 1) { + return this._data.substring(this._pos, this._pos + length); + } + + peekWhile(predicate) { + let buffer = ''; + for ( + let offset = 0, c = this._data[this._pos + offset]; + c !== undefined && predicate(c); + offset++, c = this._data[this._pos + offset] + ) { + buffer += c; + } + return buffer; + } + + // Peek first character after any characters that match predicate + peekAfter(predicate) { + const skip = this.peekWhile(predicate); + return this.peek(skip.length + 1).substring(skip.length); + } + + isNext(str) { + return this.peek(str.length) === str; + } + + next(length = 1) { + const chunk = this.peek(length); + + this._pos += chunk.length; + + this.line += this._countOccurrences(chunk, '\n'); + + const lastNewLine = chunk.lastIndexOf('\n'); + if (lastNewLine === -1) { + this.column += chunk.length; + } else { + this.column = chunk.length - lastNewLine - 1; + } + + return chunk; + } + + nextWhile(predicate) { + return this.next(this.peekWhile(predicate).length); + } + + _countOccurrences = (str, substr) => { + let count = 0; + let i = 0; + while(true) { + i = str.indexOf(substr, i); + if (i === -1) break; + i += substr.length; + count++; + } + return count; + } + + eof() { + return this.peek() === ''; + } +} diff --git a/src/errors/template_syntax_error.js b/src/errors/template_syntax_error.js new file mode 100644 index 0000000..1708da6 --- /dev/null +++ b/src/errors/template_syntax_error.js @@ -0,0 +1,7 @@ +export class TemplateSyntaxError extends Error { + constructor(cs, message) { + super( + `${cs.fileName}:${cs.line + 1}:${cs.column + 1}: ${message}` + ); + } +} diff --git a/src/template_engine.js b/src/template_engine.js new file mode 100644 index 0000000..188f15d --- /dev/null +++ b/src/template_engine.js @@ -0,0 +1,82 @@ +import { TokenStream } from './token_stream.js'; + +export class TemplateEngine { + async render(fileName) { + const ts = new TokenStream(); + await ts.loadFile(fileName); + + let buffer = ''; + + while (!ts.eof()) { + const token = ts.next(); + + switch (token.type) { + case 'raw': + buffer += this._renderRaw(token.value); + break; + case 'inline': + buffer += this._renderInline(token.value); + break; + case 'inline_unescaped': + buffer += this._renderInlineUnescaped(token.value); + break; + case 'inline_statement': + buffer += this._renderInlineStatement(token.value); + break; + case 'inline_statement_unescaped': + buffer += this._renderInlineStatementUnescaped(token.value); + break; + case 'statement': + buffer += this._renderStatement(token.value); + break; + case 'comment': + buffer += this._renderComment(token.value); + break; + default: + throw new Error(`Unrecognized token: ${token.type}`); + } + } + + return buffer; + } + + _renderComment(value) { + return `# ${value}\n`; + } + + _renderStatement(value) { + return `${value}\n`; + } + + _renderInline(value) { + return `printf '%s' "${value}" | jq -Rrj @html;\n`; + } + + _renderInlineUnescaped(value) { + return `printf '%s' "${value}";\n`; + } + + _renderInlineStatement(value) { + return `printf '%s' "$(${value})" | jq -Rrj @html;\n`; + } + + _renderInlineStatementUnescaped(value) { + return `printf '%s' "$(${value})";\n`; + } + + _renderRaw(value) { + const lines = value.split('\n'); + + let buffer = ''; + + for (let i = 0; i < lines.length; i++) { + const line = lines[i]; + const isLastLine = i === lines.length - 1; + const formatString = isLastLine ? '%s' : '%s\\n'; + + buffer += `printf '${formatString}' '${line.replace("'", "'\\''")}';\n`; + } + + return buffer; + } +} diff --git a/src/token_stream.js b/src/token_stream.js new file mode 100644 index 0000000..d060c37 --- /dev/null +++ b/src/token_stream.js @@ -0,0 +1,207 @@ +import { CharacterStream } from './character_stream.js'; +import { TemplateSyntaxError } from './errors/template_syntax_error.js'; + +export class TokenStream { + static OPEN_INLINE = '<%'; + static CLOSE_INLINE = '%>'; + static OPEN_INLINE_UNESCAPED = ''; + static OPEN_INLINE_STATEMENT = '<$%'; + static CLOSE_INLINE_STATEMENT = '%>'; + static OPEN_INLINE_STATEMENT_UNESCAPED = '<$!%'; + static CLOSE_INLINE_STATEMENT_UNESCAPED = '%>'; + static STATEMENT = '$'; + static COMMENT = '#'; + + constructor() { + this.reset(); + } + + reset() { + this._cs = new CharacterStream(); + this._peekedToken = null; + } + + loadFile(fileName) { + this.reset(); + return this._cs.loadFile(fileName); + } + + peek() { + if (!this._peekedToken) this._peekedToken = this._readNext(); + return this._peekedToken; + } + + next() { + const token = this.peek(); + this._peekedToken = null; + return token; + } + + eof() { + return this.peek() === null; + } + + _readNext() { + let raw = ''; + + const flushRaw = () => { + if (raw.length) { + const value = raw; + raw = ''; + return {type: 'raw', value}; + } + } + + while (!this._cs.eof()) { + if (this._cs.isNext(TokenStream.OPEN_INLINE)) { + return flushRaw() || this._readInline(); + } if (this._cs.isNext(TokenStream.OPEN_INLINE_UNESCAPED)) { + return flushRaw() || this._readInlineUnescaped(); + } if (this._cs.isNext(TokenStream.OPEN_INLINE_STATEMENT)) { + return flushRaw() || this._readInlineStatement(); + } if (this._cs.isNext(TokenStream.OPEN_INLINE_STATEMENT_UNESCAPED)) { + return flushRaw() || this._readInlineStatementUnescaped(); + } else if ( + this._cs.column === 0 && + this._cs.peekAfter(this._isWhitespace) === TokenStream.STATEMENT + ) { + return flushRaw() || this._readStatement(); + } else if ( + this._cs.column === 0 && + this._cs.peekAfter(this._isWhitespace) === TokenStream.COMMENT + ) { + return flushRaw() || this._readComment(); + } else { + raw += this._cs.next(); + } + } + + return flushRaw() || null; + } + + _missingInlineSpaceError(tag) { + throw new TemplateSyntaxError( + this._cs, + `Inline tag: "${tag}" must be followed by a whitespace` + ); + } + + _readInlineGeneric(tokenType, openTag, closeTag) { + this._cs.next(openTag.length); + + // Check for mandatory space + if (this._cs.peek() !== ' ') { + this._missingInlineSpaceError(openTag); + } + this._cs.next(); + + let value = ''; + while (!this._cs.eof() && !this._cs.isNext(closeTag)) { + const char = this._cs.next(); + + if (this._cs.isNext(closeTag)) { + if (char !== ' ') { + this._missingInlineSpaceError(closeTag); + } + } else { + value += char; + } + } + this._cs.next(closeTag.length); + return {type: tokenType, value}; + } + + _readInline() { + return this._readInlineGeneric( + 'inline', + TokenStream.OPEN_INLINE, + TokenStream.CLOSE_INLINE + ); + } + + _readInlineUnescaped() { + return this._readInlineGeneric( + 'inline_unescaped', + TokenStream.OPEN_INLINE_UNESCAPED, + TokenStream.CLOSE_INLINE_UNESCAPED + ); + } + + _readInlineStatement() { + return this._readInlineGeneric( + 'inline_statement', + TokenStream.OPEN_INLINE_STATEMENT, + TokenStream.CLOSE_INLINE_STATEMENT + ); + } + + _readInlineStatementUnescaped() { + return this._readInlineGeneric( + 'inline_statement_unescaped', + TokenStream.OPEN_INLINE_STATEMENT_UNESCAPED, + TokenStream.CLOSE_INLINE_STATEMENT_UNESCAPED + ); + } + + _readStatement() { + // Skip whitespace + this._cs.nextWhile(this._isWhitespace); + + // Skip STATEMENT + this._cs.next(); + + // Check for mandatory space + if (this._cs.peek() !== ' ') { + throw new TemplateSyntaxError( + this._cs, + `Statement character: "${TokenStream.STATEMENT}" must be ` + + `followed by a whitespace` + ); + } + + // Consume space + this._cs.next(); + + // Remainder of line is statement + const value = this._cs.nextWhile((c) => c !== '\n'); + + // Swallow new line + this._cs.next(); + + return {type: 'statement', value}; + } + + _readComment() { + // Skip whitespace + this._cs.nextWhile(this._isWhitespace); + + // Skip COMMENT + this._cs.next(); + + // Check for mandatory space + if (this._cs.peek() !== ' ') { + throw new TemplateSyntaxError( + this._cs, + `Comment character: "${TokenStream.COMMENT}" must be followed by a ` + + `whitespace` + ); + } + + // Consume space + this._cs.next(); + + // Remainder of line is comment + const value = this._cs.nextWhile((c) => c !== '\n'); + + // Swallow new line + this._cs.next(); + + return {type: 'comment', value}; + } + + // Utility methods + _isWhitespace(c) { + return /\s/.test(c); + } +}