这个方案错误告诉我什么？

Question

存在一个称为meep的电磁模拟器，它以guile解释器的形式提供作为前端。模拟器由一堆方案宏组成。

我想弄清楚下面的错误是什么意思。代码取自教程。当我在一个过程中包装教程时，我得到一个运行时错误，我不确定解释器（guile）告诉我什么。

不工作的代码

(define diffthick 
    (lambda (n) ; n doesn nothing 
    (
    (set! geometry-lattice (make lattice (size 16 8 no-size))) 
    (set! geometry (list 
         (make block (center 0 0) (size infinity 1 infinity) 
          (material (make dielectric (epsilon 12)))))) 
    (set! sources (list 
        (make source 
          (src (make continuous-src (frequency 0.15))) 
          (component Ez) 
          (center -7 0)))) 
    (set! pml-layers (list (make pml (thickness 1.0)))) 
    (set! resolution 10) 
    (run-until 200 
       (at-beginning output-epsilon) 
       (at-end output-efield-z)) 
    ) 
    ) 
) 
(diffthick 3) 

工作码（没有程序）

(set! geometry-lattice (make lattice (size 16 8 no-size))) 
(set! geometry (list 
       (make block (center 0 0) (size infinity 1 infinity) 
         (material (make dielectric (epsilon 12)))))) 
(set! sources (list 
       (make source 
       (src (make continuous-src (frequency 0.15))) 
       (component Ez) 
       (center -7 0)))) 

(set! pml-layers (list (make pml (thickness 1.0)))) 
(set! resolution 10) 
(run-until 200 
      (at-beginning output-epsilon) 
      (at-end output-efield-z)) 

错误

creating output file "./eps-000000.00.h5"... 
creating output file "./ez-000200.00.h5"... 
run 0 finished at t = 200.0 (4000 timesteps) 

Backtrace: 
In standard input: 
    21: 0* [diffthick 3] 
    3: 1 [#<unspecified> #<unspecified> #<unspecified> ...] 

standard input:3:5: In expression ((set! geometry-lattice #) (set! geometry #) (set! sources #) ...): 
standard input:3:5: Wrong type to apply: #<unspecified> 
ABORT: (misc-error) 

工作

----------- 
creating output file "./eps-000000.00.h5"... 
creating output file "./ez-000200.00.h5"... 
run 0 finished at t = 200.0 (4000 timesteps) 

在这一天我觉得自己喜欢的事月底被两次评估。但我不确定那是什么。

Answer 1

错误表示代码试图将(set! geometry-lattice #)的结果应用为好像它是函数，但set!结果代替#<unspecified>。发生这种情况是因为set!系列包装在包装中。

你可能寻找

(begin 
    (set! geometry-lattice ...) 
    ... 
    (run-until ...)) 

或者刚刚摆脱额外的对括号中的，因为拉姆达机构都隐含包裹在begin。