rajamesandClaude Opus 5.5
dc7e37ba5c
Ruled 2026-10-04: guard all errors. The errors that set NODE-ERROR and let the line run on now stop it at once, with a message. - A store of a non-zero code to NODE-ERROR is a trap, a sixth kind of fault: nothing after it executes, the return stack is emptied, and the data stack is left as the word left it. Not attached, NODE-ERROR is plain memory, as the tests below the prompt use it. - The capsule's words store a code where they stored -1, and the prompt's (RAISED) prints its message: Negative count, Not a number, Number too long, Not a character, Dictionary full, Name missing, Control structure mismatch, Control structures too deep. - ' and COMPILE and [COMPILE] of a word that is not there say UNKNOWN WORD: 'xxx', as the interpreter does. - tests: the trap in test_exec.c; every message from the prompt, with the rest of the line not run and the stack kept, in test_host_quit.c. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
194 lines
8.4 KiB
Plaintext
194 lines
8.4 KiB
Plaintext
\ input.v4 -- reading a line and splitting it into words and numbers.
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\
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\ DECOMPOSITION.md 5.9: TIB >IN SPAN SOURCE BL EXPECT QUERY WORD ENCLOSE
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\ CONVERT NUMBER, and the comment words ( and \ of 5.15 (named PAREN and
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\ BACKSLASH here, since the text assembler reads those two characters as its
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\ own comments; the dictionary will give them their names). Part of the compiler
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\ capsule: it runs on the host node. Rests on core.v4.
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\
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\ Constants the loader supplies:
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\ TIB byte address of the text input buffer; QUERY fills at most 81 bytes
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\ >IN word address of the variable: offset in TIB of the next character
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\ SPAN word address of the variable: how many characters the last
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\ EXPECT or QUERY read
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\ WBUF byte address of WORD's buffer, 257 bytes
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\ (P) word address of eight cells of scratch for this file
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\ TIB >IN SPAN and BL are in-line: written in a definition they are literals.
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macro BL 32 endmacro
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\ ( -- baddr u ) the input buffer and how much of it is in use
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header SOURCE
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: SOURCE TIB SPAN a! @ -if P drop 0 P: ;
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\ ( baddr n -- ) FORTH-79: characters from the terminal are stored from
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\ baddr upward until a new-line or until n have been received; the new-line
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\ is taken but not stored. A zero is added after the text, so the buffer
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\ must hold n + 1 bytes. No action for n <= 0. SPAN is how many characters
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\ were stored (SPAN is not FORTH-79; v3 has it). A line longer than n leaves
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\ the rest, its new-line included, to be read next.
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\ It is what the prompt reads every line with, with whatever the user has left
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\ on the stack beneath it, so it works in (P) -- (P)+0 where the next
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\ character goes, (P)+1 how many more may come, (P)+2 where the first went --
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\ and has at most three cells of its own on the data stack (D-2).
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header EXPECT
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: EXPECT
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-if NN drop drop ; \ n < 0
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NN: if ZERO
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(P)+1 a! ! dup (P)+2 a! ! (P) a! !
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L: (P)+1 a! @ if END drop
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KEY dup -10 + if NL drop \ c
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(P) a! @ C!
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(P) a! @ 1 + ! (P)+1 a! @ -1 + !
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jump L
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NL: drop drop jump FIN
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END: drop
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FIN: 0 (P) a! @ C!
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(P) a! @ (P)+2 a! @ - SPAN a! ! ;
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ZERO: drop drop ;
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\ ( -- ) FORTH-79: up to 80 characters, or a line, into TIB; >IN to 0.
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header QUERY
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: QUERY TIB 80 EXPECT 0 >IN a! ! ;
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\ ---- WORD ------------------------------------------------------------------
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\ WORD is called from deep inside the interpreter and compiler, with whatever
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\ the user has on the stacks beneath it, and the stacks are ten and nine deep
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\ (D-2). So everything it works on is in (P), and it never has more than
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\ three cells of its own on the data stack:
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\ (P)+0 the delimiter (P)+1 the length of the text in TIB
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\ (P)+2 the word's length (P)+3 how much of it is still to be copied
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\ (P)+6 where it is in TIB (P)+7 where the word starts
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\ (CONVERT and NUMBER use (P)+2 .. (P)+5; they and WORD never run inside
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\ each other.)
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\ In line, not called: WORD may have only a few return entries to spare.
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macro (LEFT) (P)+6 a! @ (P)+1 a! @ - endmacro \ ( -- d ) d < 0 while inside the text
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macro (CH) (P)+6 a! @ TIB + C@ (P) a! @ xor endmacro \ ( -- x ) x = 0 at a delimiter
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macro (STEP) (P)+6 a! @ 1 + ! endmacro
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\ ( c -- baddr ) FORTH-79: characters are taken from TIB until the
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\ delimiter c or the end of the text, leading delimiters ignored, and stored
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\ in WBUF as a counted string. The delimiter met -- c, or a zero if the text
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\ ran out -- is stored after them and is not counted. >IN is left just past
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\ that delimiter. With nothing left the count is 0. The count is a byte,
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\ so a word longer than 255 characters is cut to 255.
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\ The three parts of WORD. The first is called and returns before anything
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\ else is; the last is jumped to; so WORD's calls of C@ and C! are no deeper
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\ than if it were written in one piece.
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: (WORD-SET) ( c -- )
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255 and (P) a! !
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SPAN a! @ -if A drop 0 A: (P)+1 a! !
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>IN a! @ -if B drop 0 B: (P)+6 a! ! ;
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: (WORD-TAKE) ( -- baddr )
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(P)+6 a! @ (P)+7 a! ! \ where it starts
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SC: (LEFT) -if SCE drop (CH) if SCE drop (STEP) jump SC \ up to a delimiter
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SCE: drop
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(P)+6 a! @ (P)+7 a! @ - \ its length
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dup -256 + -if CAP drop jump FITS CAP: drop drop 255 FITS:
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dup (P)+2 a! ! (P)+3 a! !
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(P)+2 a! @ WBUF C!
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\ copy it, last character first
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CP: (P)+3 a! @ if COPIED -1 + dup ! \ k
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dup (P)+7 a! @ + TIB + C@ \ k c
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SWAP WBUF+1 + C!
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jump CP
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COPIED: drop
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(LEFT) -if RANOUT
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drop (P) a! @ (P)+2 a! @ WBUF+1 + C! \ the delimiter after the text
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(P)+6 a! @ 1 + >IN a! ! WBUF ;
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RANOUT: drop 0 (P)+2 a! @ WBUF+1 + C!
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(P)+6 a! @ >IN a! ! WBUF ;
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header WORD
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: WORD
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(WORD-SET)
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SK: (LEFT) -if SKE drop (CH) if SKS drop jump (WORD-TAKE) \ past delimiters
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SKS: drop (STEP) jump SK
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SKE: drop jump (WORD-TAKE)
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\ ( c -- baddr ) as WORD, but leading delimiters are not ignored: the text
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\ starts at >IN, and may be empty. This is what ." needs: ." " is an
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\ empty string, where WORD would step over its closing quote.
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: (PARSE) (WORD-SET) jump (WORD-TAKE)
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\ ---- ENCLOSE ---------------------------------------------------------------
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\ (P)+0 the delimiter, (P)+1 the string's address.
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: (E?) ( i -- i k ) \ k: 0 at the end of the string, 1 at a delimiter, else 2
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dup (P)+1 a! @ + C@ if END (P) a! @ xor if DEL drop 2 ;
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DEL: drop 1 ;
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END: drop 0 ;
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: (ESKIP) ( i -- i' ) L: (E?) -1 + if S drop ; S: drop 1 + jump L
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: (ESCAN) ( i -- i' ) L: (E?) -2 + if S drop ; S: drop 1 + jump L
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\ ( baddr c -- baddr n1 n2 n3 ) in the zero-terminated string at baddr:
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\ n1 the offset of the first character that is not c, n2 the offset of the
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\ first c after it, n3 the offset of the first character after that run of c.
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header ENCLOSE
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: ENCLOSE
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255 and (P) a! ! dup (P)+1 a! !
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0 (ESKIP) dup (ESCAN) dup (ESKIP) ;
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\ ---- CONVERT and NUMBER ----------------------------------------------------
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\ ( c -- n ) the value of the digit c, 0 .. 35, in either case; -1 if none
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: (DIGIT)
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dup -48 + -if GE0 drop drop -1 ;
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GE0: drop dup -58 + -if GT9 drop -48 + ;
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GT9: drop dup -65 + -if GEA drop drop -1 ;
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GEA: drop dup -91 + -if GTZ drop -55 + ;
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GTZ: drop dup -97 + -if GEa drop drop -1 ;
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GEa: drop dup -123 + -if GTz drop -87 + ;
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GTz: drop drop -1 ;
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\ ( d1 baddr1 -- d2 baddr2 ) FORTH-79: the characters from baddr1 + 1 on are
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\ taken as digits in the current BASE, each accumulated into the double after
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\ it is multiplied by BASE, until one is not a digit; baddr2 is its address.
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\ (P)+2 holds the digit while the double is multiplied and (P)+5 the address,
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\ so nothing waits on the return stack across the calls.
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header CONVERT
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: CONVERT
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L: 1 + dup (P)+5 a! ! C@ (DIGIT) \ lo hi n
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-if DIG drop (P)+5 a! @ ;
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DIG: dup (BASE) - -if BIG
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drop (P)+2 a! ! \ lo hi
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(BASE) UM* drop \ lo hi*base
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SWAP (BASE) UM* \ hi*base plo phi
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push SWAP pop + \ plo hi'
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(P)+2 a! @ 0 D+
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(P)+5 a! @ jump L
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BIG: drop drop (P)+5 a! @ ;
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\ ( baddr -- d flag ) the counted string at baddr as a signed double in the
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\ current BASE, and -1; it may begin with a minus sign. If it is empty, is
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\ only a sign, or holds anything that is not a digit: 0 0 and 0. The character after the string must not be a digit
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\ (WORD puts the delimiter or a zero there); if it is, that too is reported
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\ as an error. (P)+3 the address of its last character, (P)+4 the sign.
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: (NUMBER?)
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dup C@ if ERR2
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over + (P)+3 a! ! \ baddr
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dup 1 + C@ -45 + if NEG
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drop 0 (P)+4 a! ! jump GO
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NEG: drop -1 (P)+4 a! ! 1 +
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dup (P)+3 a! @ xor if ERR2 drop
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GO: push 0 0 pop CONVERT \ lo hi baddr2
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(P)+3 a! @ 1 + xor if FINE
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drop drop drop jump ERR0
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FINE: drop (P)+4 a! @ if POS drop DNEGATE -1 ;
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POS: drop -1 ;
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ERR2: drop drop
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ERR0: 0 0 0 ;
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\ ( baddr -- d ) FORTH-79. What is not a number gives 0 and sets NODE-ERROR.
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header NUMBER
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: NUMBER
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(NUMBER?) if BAD drop ;
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BAD: drop NODE-ERROR b! 2 !b ;
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\ ---- comments (5.15) -------------------------------------------------------
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\ PAREN skips to the closing parenthesis; BACKSLASH skips the rest of the line.
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header ( immediate
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: PAREN 41 WORD drop ;
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header \ immediate
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: BACKSLASH SPAN a! @ >IN a! ! ;
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