Scanning—Theory and Practice - Crafting a Compiler - page 74

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(" ")+ { /* delete blanks */}

f { return(FLOATDCL); }

i { return(INTDCL); }

p { return(PRINT); }

[a-eghj-oq-z] { return(ID); }

([0-9]+)|([0-9]+"."[0-9]+) { return(NUM); }

"=" { return(ASSIGN); }

"+" { return(PLUS); }

"-" { return(MINUS); }

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Figure 3.11: A Lex definition for ac's tokens.

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Blank

" "

Digits [0-9]+

Non_f_i_p [a-eghj-oq-z]

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{Blank}+ { /* delete blanks */}

f { return(FLOATDCL); }

i { return(INTDCL); }

p { return(PRINT); }

{Non_f_i_p} { return(ID); }

{Digits}|({Digits}"."{Digits}) { return(NUM); }

"=" { return(ASSIGN); }

"+" { return(PLUS); }

"-" { return(MINUS); }

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Figure 3.12: An alternative definition for ac's tokens.