;+ ; Procedure: calc ; ; Purpose: This routine takes a string as input and interprets the string as a mini-language. ; This language can manipulate normal idl variables and tplot variables. The idl variables ; that can be modified are non-system variables in the scope in which the procedure is called. ; ; Inputs: s : A string that will be interpreted as the mini language ; ; Keywords: error: ; If an error occurs during processing this keyword will return a struct ; that contains information about the error. If error is set at time of input ; this routine will set it to undefined, before it interprets 's' to prevent internal errors. ; ; function_list: return an array of strings that lists of the names/syntax of ; available functions in the mini_language. Return without processing 's' ; if an argument in the returned name is in brackets it is optional ; for example: min(x[,dim]) ; operator_list: return an array of strings that lists of the names of available ; operators in the mini_language. Return without processing 's' ; ; verbose: set this keyword if you want the routine to print errors to screen rather ; than only return them via error ; ; gui_data_obj: If 'calc' is being used inside the gui, then the loaded_data object will ; be passed in through this keyword. NOTE: end users should not even set ; this argument. ; ; Outputs: none, but it will modify various variables in your environment ; ; Examples: ; calc,'a = 5' ; calc,'"pos_re" = "tha_state_pos"/6374' ; calc,'a += 7' ; calc,'"tvar" = "tvar" + var' ; calc,'"tvar" = ln("tvar")' ; calc,'"tvar" = total("tvar"+3,2)' ; calc,'"tvar" = -a + 5.43e-7 ^ ("thb_fgs_dsl_x" / total("thb_fgs_dsl_x")) ; calc,operator_list=o,function_list=f ; ; Notes: ; 1. The language generally uses a fairly straightforward computational syntax. The main ; difference from idl is that quoted strings are treated as tplot variables in this language ; 2. A full specification of language syntax in backus-naur form can be found ; in the file bnf_formal.txt, the programmatic specification of this syntax ; can be found in productions.pro ; 3. The language is parsed using an slr parser. The tables required to do this parsing ; are generated and stored ahead of time in the file grammar.sav and parse_tables.sav ; 4. The routines that describe the evaluation rules for the language can be found in the file ; mini_routines.pro ; 5. If you want to modify the way the language works you'll probably need to modify productions.pro, ; regenerate the slr parse tables using save_calc_tables and modify/add routines to mini_routines.pro ; 6. Arrays must have the same dimensions to be combines, and tplot variables must also have the same times. ; 7. Procedures: min,max,mean,median,count,total all take a second argument that allow you to select the ; dimension over which the operation is performed ; ; See Also: ; All routines in the ssl_general/mini directory ; The techniques used for this interpreter are based on two books: ; ; 1. Compilers:Principles,Techniques,and Tools by Aho,Sethi,& Ullman 1988 (esp. Ch3) ; ; 2. Structure & Interpretation of Computer Programs by Abelson & Sussman 1996 (esp. Ch4) ; ; If you want to understand/modify this program it may help to use these books as ; a reference. ; ; Also see: thm_crib_calc.pro for examples of usage ; ; ToDo: 1. Implement Constants ; 2. Implement 0 argument functions ; 3. Implement keywords for functions ; 4. Implement procedures ; 5. Implement control statements ; 6. Optional auto-interpolation ; ; $LastChangedBy: pcruce $ ; $LastChangedDate: 2009-03-03 13:30:32 -0800 (Tue, 03 Mar 2009) $ ; $LastChangedRevision: 5202 $ ; $URL: svn+ssh://thmsvn@ambrosia.ssl.berkeley.edu/repos/ssl_general/tags/tdas_5_11/mini/calc.pro $ ;- ;- pro calc,s,error=error,function_list=function_list,operator_list=operator_list,verbose=verbose,gui_data_obj=gui_data_obj compile_opt idl2 ;clear error if set at time of input if keyword_set(error) then begin t = temporary(error) endif ;if requested return list of functions if arg_present(function_list) then begin mini_routines list = (function_list()).name ;apply syntax description...this should probably be done in the function_list routine list[*] += '(x' list[[0,2]] += '[,base]' list[23:*] += '[,dim]' list[*] += ')' function_list = list endif if arg_present(operator_list) then begin mini_routines list = (operator_list()).name ;replace unary/binary minus codes with normal minus ;...this should probably be done in the operator_list routine operator_list = [list[0:2],'-',list[5:*]] endif if arg_present(operator_list) || arg_present(function_list) then begin return endif ;check that arg is set if ~keyword_set(s) then begin error = {type:'error',name:'Input string not set',value:'s'} return endif ;get path of routine rt_info = routine_info('calc',/source) path = file_dirname(rt_info.path) + '/' ;read grammar and parse table information from file restore,path+'grammar.sav' restore,path+'parse_tables.sav' if ~keyword_set(gui_data_obj) || ~obj_valid(gui_data_obj) then begin gui_data_obj = obj_new() endif ;set global variables mini_globals = {scope_level:scope_level()-1,gui_data_obj:gui_data_obj} defsysv,'!mini_globals',mini_globals ;split the input string into a list of tokens lex,s,token_list=token_list,error=error if keyword_set(error) then begin if keyword_set(verbose) then begin if in_set('VALUE',tag_names(error)) then begin for i = 0,n_elements(error.value)-1 do begin print,error.value[i] endfor endif else begin dprint,error endelse endif return endif if is_endline_type(token_list[0]) then return ;evaluate the list of tokens using the parse table and grammar provided evaluate,token_list,grammar,parse_tables,error=error if keyword_set(error) then begin if keyword_set(verbose) then begin if in_set('VALUE',tag_names(error)) then begin for i = 0,n_elements(error.value)-1 do begin print,error.value[i] endfor endif else begin dprint,error endelse endif return endif return end