code: function appendExpression(prefix, token, suffix, isString) {
  		if (state === 'very-first') {
  			if (!isString) {
  				builder.add('""+')
  			}
  		} else if (state === 'first') {
  			builder.add('__o+=')
  		} else {
  			builder.add('+')
  		}
  
  		if (options.compileDebug && token) {
  			builder.add(`(${getDebugMarker(token)},`)
  		}
  		if (prefix) {
  			builder.add(prefix)
  		}
  		if (token) {
  			if (token.type === 'source-builder') {
  				builder.addBuilder(token.sourceBuilder)
  			} else {
  				builder.addToken(token)
  			}
  		}
  		if (suffix) {
  			builder.add(suffix)
  		}
  		if (options.compileDebug && token) {
  			builder.add(')')
  		}
  
  		state = 'rest'
  	}
docs: Append an expression that contributes directly to the output
  @param {?string} prefix
  @param {?Token|SourceBuilder} token
  @param {?string} suffix
  @param {boolean} isString - whether this expression certainly evaluates to a string